Answer:
This is a right-tailed test because a direction is specified. The population parameter is greater than the specified value.
Step-by-step explanation:
The hypothesis testing technique is used to test an assumption regarding population parameter. Null hypothesis is a statement that is to be tested against the alternative hypothesis and then decision is taken whether to accept or reject the null hypothesis. A right tailed test is where the most of data is in the right side. This is one tailed test where the direction is specified.
Complete the equation describing how
x and y are related.
X
-2
-1
D
у
12
8
0
-8
E 12
y = [? ]x
Enter the answer that belongs in [?]
Answer:
y= -(4x)
Step-by-step explanation:
Look at the image for the question.
Answer:
38 cm^2
Step-by-step explanation:
The surface area of a rectangular prism is
SA = 2(lw+wh+lh) where h is the height l is the length and w is the width
SA = 2( 3*1 + 3*4+4*1)
= 2(3+12+4)
= 2(19)
= 38 cm^2
A number plus its fifth add up to 17 What is the number
Answer:
Step-by-step explanation:
we call the number X
x/5 is the fifth part of that number
I propose equality:
x + x/5 = 17
we add the fractions on the left side:
6x/5 = 17
We pass 5 to multiply to the other side:
6x = 5 * 17
6x = 85
we clear x
x = 85/6
x = 14.17
test
14.17 + 2.83 = 17
okay
Answer:
14.1666666667
Step-by-step explanation:
We can write the equation as:
x + x/5 = 17
=> 5/5x + 1/5x = 17
=> 6/5x = 17
=> 6x = 17 * 5
=> 6x = 85
=> x = 85/6
=> x = 14.1666666667
Let's check whether our answer is correct
=> 14.1666666667 + 14.1666666667 / 5 = 17
=> 14.1666666667 + 2.83333333333 = 17
=> 17 = 17
So, the answer is 14.1666666667
suppose a chemical engineer randomly selects 3 catalysts for testing from a group of 10 catalysts, 6 of which have low acidity & 4 have high acidity. What is the probability that exactly2 lower acidic catalysts are selected?
Step-by-step explanation:
Total catalysts = 10
Probability of 2 lower acidic catalysts = 2/10 = 1/5
Elena drank 3 liters of water yesterday. Jada drank 3/4 times as much water as elena. Link drank twice as much as Jada. Did jada drink more or less then elena? Explain how you know
Answer:
Step-by-step explanation:
3\4 bc on a nuberline it would be 3 3\4
I--I----(etc)
so yeah hope i helped
A semicircular plate with radius 7 m is submerged vertically in water so that the top is 3 m above the surface. Express the hydrostatic force against one side of the plate as an integral and evaluate it. (Round your answer to the nearest whole number. Use 9.8 m/s2 for the acceleration due to gravity. Recall that the weight density of water is 1000 kg/m3.)
Answer:
F = 585844 N
Step-by-step explanation:
Given that:
A semicircular plate with radius 7 m is submerged vertically in water so that the top is 3 m above the surface.
The objective of this question is to express the hydrostatic force against one side of the plate as an integral and evaluate it.
To start with the equation of a circle: a² + b² = r²
The equation of circle with radius r = 7 can be expressed as:
a² + b² = 7²
a² + b² = 49
b² = 49 - a²
b = [tex]\sqrt{49 -a}[/tex]
NOW;
The integral of the hydrostatic force with a semicircular plate with radius 7 m and the top is 3 m above the surface can be calculated as follows:
[tex]\mathtt{F = 2 \rho g \int \limits^7_3 (a -3) \sqrt{49 -y^2} \ \ da}[/tex]
[tex]\mathtt{F = 2 \rho g \begin {pmatrix}\dfrac{\sqrt{49 -a^2} \ (2a^2-9a - 98)-(441 \times sin^{-1} (\dfrac{a}{3})) }{6} \end{pmatrix}}[/tex]
where;
density of water is 1000 kg/m3
and acceleration due to gravity is 9.8 m/s
Solving the integral; we have:
F = 2 × 1000 kg/m³ × 9.8 m/s × (29.89)
F = 585844 N
Consider the age distribution in the United States in the year 2075 (as projected by the Census Bureau). Construct a cumulative frequency plot and describe what information the plot communicates about the distribution of ages in the future.
Answer:
The cumulative frequency plot is also attached below.
Step-by-step explanation:
The data provided is as follows:
Age Group Frequency
0 - 9 34.9
10 - 19 35.7
20 - 29 36.8
30 - 39 38.1
40 - 49 37.8
50 - 59 37.8
60 - 69 34.5
70 - 79 27.2
80 - 89 18.8
90 - 99 7.7
100 - 109 1.7
Consider the Excel output attached.
The cumulative frequency are computed in the Excel sheet.
The cumulative frequency plot is also attached below.
From the cumulative frequency plot it can be seen that in the future most people will belong to a higher age group rather then the lower ones.
A circle has center (3, -5) and the point (-1, -8) lies on the circumference of the circle. What is the equation of the circle in Standard Form?
Answer:
[tex] {(x - 3)}^{2} + {(y + 5)}^{2} = {5}^{2} [/tex]
Step-by-step explanation:
First find the radius
Which is the distance between the 2 points.
Radius =5
The answer in the standad form is above.
The equation of the circle in Standard Form is (x - 3)² + (y + 5)² = 25
The standard equation of a circle is given as:
(x - a)² + (y - b)² = r²
where (a, b) is the center of the circle and r is the radius of the circle.
Given the center as (3, -5) hence the radius of the circle is the distance between (3, -5) and (-1, -8). Hence:
[tex]Radius=\sqrt{(-8-(-5))^2+(-1-3)^2} \\\\Radius=5\ units\\[/tex]
hence:
(x - 3)² + (y - (-5))² = 5²
(x - 3)² + (y + 5)² = 25
The equation of the circle in Standard Form is (x - 3)² + (y + 5)² = 25
Find out more at: https://brainly.com/question/13658927
The company charges $5 per sq ft, AND has a minimum charge of 3 sq ft per order (meaning if a customer orders something SMALLER than 3 sq ft they still are charged as if they ordered 3 sq ft, never less - but if they order something larger than 3 sq ft they just pay regularly by the sq ft). What would you charge someone who orders a piece of glass 12in X 12in
Using the same sq ft charge ($5 per sq ft) and remembering the rule about when to use the minimum charge, what would you charge someone ordering a piece of glass 48in X 48in? *
Answer:
12 inches by 12 inches = 15 dollars
48 inches by 48 inches = 80 dollars
Step-by-step explanation:
12 inches = 1 ft
so 12 inch by 12 inches is 1 ft * 1 ft
1 ft* 1 ft
1 ft^2
This is smaller than 3 ft^2 so they will get charged for 3 ft^2
3 ft^2 = 3 ft^2 * $5 / ft^2 = 15 dollars
48 inches = 48/12 = 4 ft
4ft * 4 ft = 16 ft^2
16 ft^2 = 16 ft^2 * $5 / ft^2 = 80 dollars
Find the sum to infinity of the series 2+5/4+11/16+23/64+..........up to the infinity.
infinity
We have
[tex]2+\dfrac54+\dfrac{11}{16}+\dfrac{23}{64}+\cdots=\displaystyle\sum_{n=0}^\infty\frac{3\cdot2^n-1}{4^n}[/tex]
(notice that each denominator is a power of 4, and each numerator is one less than some multiple of 3, in particular 3 times some power of 2)
Recall for [tex]|x|<1[/tex], we have
[tex]\displaystyle\frac1{1-x}=\sum_{n=0}^\infty x^n[/tex]
So we have
[tex]\displaystyle\sum_{n=0}^\infty\frac{3\cdot2^n-1}4=3\sum_{n=0}^\infty\left(\frac12\right)^n-\sum_{n=0}^\infty\left(\frac14\right)^n=\frac3{1-\frac12}-\frac1{1-\frac14}=\boxed{\frac{14}3}[/tex]
20 applicants are interviewed for a job. The interviewer creates an ordered list (first to last) of the best 6 applicants. How many ways are
Answer:
38,760 different ways.Step-by-step explanation:
The question is incomplete. Here is the complete question.
20 applicants are interviewed for a job. The interviewer creates an ordered list (first to last) of the best 6 applicants. How many ways are there for the interviewer to create the list?
Since the question deals with selection, we will apply the combination rule. Generally, if r objects are to be selected from n pool of objects, this can be done in nCr number of ways.
nCr = n!/(n-r)!r!
According to the question, if the the interviewer is to select 6 applicants from a pool of 20 applicants that are interviewed for a job, this can be done in 20C6 number of ways.
20C6 = 20!/(20-6)!6!
20C6 = 20!/14!6!
20C6 = 20*19*18*17*16*15*14!/14!*6*5*4*3*2
20C6 = 20*19*18*1716*15/6*5*4*3*2
20C6 = 27,907,200/720
20C6 = 38,760 different ways.
Hence, the interviewer can create the list in 38,760 different ways.
The art teacher bought 19 sketchbooks for $2.98 per book. What equation can be used to find the total cost of the sketchbooks?
Answer:
y = 2.98x
Step-by-step explanation:
x = number of sketchbooks
y = total cost
urgent !!!!!!!!!!!!!!! 10 points
Answer:
136 cm²
Step-by-step explanation:
Surface area = 2(lw+wh+hl)
l = 7
w = 2
h = 6
so,
2(7×2+2×6+7×6)
= 136 cm²
Answer:
136 cm^2
Step-by-step explanation:
L 7cm
W 6cm
D 2cm
7 x 6 + 6 x 2 + 2 x 7 (x 2) = 68 x 2 = 136cm^2
A TV Dinner Company Sells Three Types Of Dinners: A Chicken Dinner For $10, A Beef Dinner For $11, Or A Fish Dinner For $12. At One Particular Grocery Store, They Sold 200 Dinners For A Grand Total Of $2138. Required:a. If they sold three times as many chicken dinners as they did fish, then how many of each kind of dinner did they sell?b. Find the equation of the quadratic function that passes through the points (−1, 9), (2, 6), and (3, 17). Write your answer in the form y = ax2+bx+c.
Answer:
a) The company sold 93 Chicken dinners, 76 Beef dinners and 31 Fish dinners.
b) [tex]y=3x^{2}-4x+2[/tex]
Step-by-step explanation:
a)
In order to solve part a of the problem, we must start by setting our variables up:
C=# of Chicken dinners
B=# of Beef dinners
F=# of Fish dinners
Next we can use these variables to build our equations. We start by taking the fact that they sold a total of 200 dinners. The sum of all the variables should add up to that so we get:
C+B+F=200
Then the problem tells us the price of each dinner and the total amount of money they made from selling the dinners that day:
"A TV Dinner Company Sells Three Types Of Dinners: A Chicken Dinner For $10, A Beef Dinner For $11, Or A Fish Dinner For $12. For A Grand Total Of $2138"
So we can use this information to build our second equation:
10C+11B+12F=2138
We have two equations now but three variables, so we need an additional equation so we can finish solving this. The problem tells us that:
"they sold three times as many chicken dinners as they did fish"
which translates to:
C=3F
so now we have enough information to finish solving the problem. We can start by substituting the last equation into the previous two equations so we get:
C+B+F=200
3F+B+F=200
4F+B=200
and
10C+11B+12F=2138
10(3F)+11B+12F=2138
30F+11B+12F=2138
42F+11B=2138
So now we can take the two bolded equations and solve them simultaneously. We can solve them by using any method we wish. Let's solve it by substitution.
We start by solving the first equation for B so we get:
B=200-4F
and now we substitute it into the second equation:
42F+11(200-4F)=2138
and now we solve for F
42F+11(200-4F)=2138
42F+2200-44F=2138
-2F=2138-2200
[tex]F=\frac{-62}{-2}[/tex]
F=31
So now that we know the value of F, we can find the values of the rest of the variables so we can take the previous equations to figure this out:
B=200-4F
B=200-4(31)
B=200-124
B=76
and finally:
C=3F
C=3(31)
C=93
So
The company sold 93 Chicken dinners, 76 Beef dinners and 31 Fish dinners.
b) For the second part of the problem we need to build a system of equations to find the equation we are looking for. We were given three points:
(-1,9), (2,6) and (3,17)
so we need to substitute each of the points on the given quadratic equation so we get:
[tex]9=a(-1)^{2}+b(-1)+c[/tex]
eq.1: [tex]9=a-b+c[/tex]
[tex]6=a(2)^{2}+b(2)+c[/tex]
eq. 2: [tex]6=4a+2b+c[/tex]
[tex]17=a(3)^{2}+b(3)+c[/tex]
eq. 3: [tex]17=9a+3b+c[/tex]
So now that we have our three equations we can solve them simultaneously to get the values of a, b and c by using the method you feel more comfortable with. Let's solve it by elimination:
So let's take the first equations and let's subtract them:
[tex]9=a-b+c[/tex]
[tex]-6=-4a-2b-c[/tex]
-------------------------------
3=-3a-3b
And now we repeat the process with the first and third equations:
[tex]9=a-b+c[/tex]
[tex]-17=-9a-3b-c[/tex]
-------------------------------
-8=-8a-4b
So now we have two new equations we can solve simultaneously, but they can be simplified by dividing the first one into -3 and the second one into -4 so they become:
a+b=-1
2a+b=2
We can now solve them by substitution. Let's solve the first one for a and then let's substitute it into the second equation:
a=-1-b
let's substitute
2(-1-b)+b=2
and solve for b
-2-2b+b=2
-b=4
b=-4
Now we can find a:
a=-1-b
a=-1+4
a=3
and now we can find c:
c=9-a+b
c=9-3-4
c=2
So we can use these answers to build our equation:
[tex]y=ax^{2}+bx+c[/tex]
[tex]y=3x^{2}-4x+2[/tex]
Carmen Martinez
What is the slope of the line that passes through the point 4,4 and 10,7 write your answer in simplest form
[tex]\boxed{\sf Slope(m)=\dfrac{y_2-y_1}{x_2-x_1}}[/tex]
[tex]\\ \sf\longmapsto m=\dfrac{7-4}{10-4}[/tex]
[tex]\\ \sf\longmapsto m=\dfrac{3}{6}[/tex]
[tex]\\ \sf\longmapsto m=\dfrac{1}{2}[/tex]
[tex]\\ \sf\longmapsto m\approx0.5[/tex]
Answer:
[tex]m=\frac{1}{2}[/tex]
Step-by-step explanation:
The slope of a line, also known as the change in the line or the ([tex]\frac{rise}{run}[/tex]) can be found using the following formula,
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]
Where ([tex]x_1,y_1[/tex]) and ([tex]x_2,y_2[/tex]) are points on the line. Substitute the given information into the formula and solve for the slope.
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]
Points on the line: [tex](4,4)\ \ \ (10, 7)[/tex]
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]
[tex]m=\frac{7-4}{10-4}[/tex]
[tex]m=\frac{3}{6}[/tex]
[tex]m=\frac{1}{2}[/tex]
[tex]m=0.5[/tex]
Operations and scientific notation math project need to know how to find the scientific notation
Answer:
how did not orderstan that
You are starting a sock company. You must determine your costs to manufacture your product. The start-up cost is $2000 (which helps you purchase sewing machines). Material and labor is $2.50 per pair of socks.
a. Write an equation to model your company’s cost for manufacturing the socks. (i.e. y=mx+b)
b. Which variable represents the domain? Explain your answer.
c. What is the domain for this situation?
d. Which variable represents the range? Explain your answer.
e. What is the range for this situation?
f. Using your equation, what would be the cost of manufacturing 25 pairs of socks?
g. How many socks could you make with $2500?
h. Create a coordinate graph on a sheet of paper to represent this situation. Describe the graph. Include the dimensions you would use for the x and y axes.
PLS HELP ASAP!
a. y = 2.5x + 2000
b. The variable x represents the domain because the domain is the range of the possible x values.
c. x ≥ 0
d. The variable y represents the range because the range is the range of the possible y values.
e. y ≥ 2000
f. y = 2.5(25) + 2000
y = 62.5 + 2000
y = $2062.50
g. 2500 = 2.5x + 2000
2.5x = 500
x = 200
h. I am sorry I cannot make the graph but hopefully you can figure out how to make it using the info I have given in the above parts of the problem :)
g Jack is polling New Yorkers to determine what proportion of them want to legalize recreational marijuana. How many New Yorkers should the sample to ens
Answer:
1006
Step-by-step explanation:
Take proportion, p = 62%
n = (Z² * pq) / M.E²
Margin error = 0.03
p = 62% = 0.62
q = 1 - p = 1 - 0.62 = 0.38
Zcritical at 95% = 1.96
n = (1.96² * (0.62*0.38)) / 0.03²
n = 0.90508096 / 0.0009
n = 1005.6455
n = 1006
Sample size = 1006
Mr. Vazquez determines that the area of a bathroom in his house is 25 square feet less than 1/5 of the area of the living room. If the bathroom measures 35 square feet, what is the area of the living room?\
Answer:
300 SF
Step-by-step explanation:
just took the test
A random sample of 12 supermarkets from Region 1 had mean sales of 84 with a standard deviation of 6.6. A random sample of 17 supermarkets from Region 2 had a mean sales of 78.3 with a standard deviation of 8.5. Does the test marketing reveal a difference in potential mean sales per market in Region 2? Let μ1 be the mean sales per market in Region 1 and μ2 be the mean sales per market in Region 2. Use a significance level of α=0.02 for the test. Assume that the population variances are not equal and that the two populations are norm
Answer:
We conclude that there is no difference in potential mean sales per market in Region 1 and 2.
Step-by-step explanation:
We are given that a random sample of 12 supermarkets from Region 1 had mean sales of 84 with a standard deviation of 6.6.
A random sample of 17 supermarkets from Region 2 had a mean sales of 78.3 with a standard deviation of 8.5.
Let [tex]\mu_1[/tex] = mean sales per market in Region 1.
[tex]\mu_2[/tex] = mean sales per market in Region 2.
So, Null Hypothesis, [tex]H_0[/tex] : [tex]\mu_1-\mu_2[/tex] = 0 {means that there is no difference in potential mean sales per market in Region 1 and 2}
Alternate Hypothesis, [tex]H_A[/tex] : > [tex]\mu_1-\mu_2\neq[/tex] 0 {means that there is a difference in potential mean sales per market in Region 1 and 2}
The test statistics that will be used here is Two-sample t-test statistics because we don't know about population standard deviations;
T.S. = [tex]\frac{(\bar X_1 -\bar X_2)-(\mu_1-\mu_2)}{s_p \times \sqrt{\frac{1}{n_1}+ {\frac{1}{n_2}}} }[/tex] ~ [tex]t__n_1_+_n_2_-_2[/tex]
where, [tex]\bar X_1[/tex] = sample mean sales in Region 1 = 84
[tex]\bar X_2[/tex] = sample mean sales in Region 2 = 78.3
[tex]s_1[/tex] = sample standard deviation of sales in Region 1 = 6.6
[tex]s_2[/tex] = sample standard deviation of sales in Region 2 = 8.5
[tex]n_1[/tex] = sample of supermarkets from Region 1 = 12
[tex]n_2[/tex] = sample of supermarkets from Region 2 = 17
Also, [tex]s_p=\sqrt{\frac{(n_1-1)\times s_1^{2}+(n_2-1)\times s_2^{2} }{n_1+n_2-2} }[/tex] = [tex]s_p=\sqrt{\frac{(12-1)\times 6.6^{2}+(17-1)\times 8.5^{2} }{12+17-2} }[/tex] = 7.782
So, the test statistics = [tex]\frac{(84-78.3)-(0)}{7.782 \times \sqrt{\frac{1}{12}+ {\frac{1}{17}}} }[/tex] ~ [tex]t_2_7[/tex]
= 1.943
The value of t-test statistics is 1.943.
Now, at a 0.02 level of significance, the t table gives a critical value of -2.472 and 2.473 at 27 degrees of freedom for the two-tailed test.
Since the value of our test statistics lies within the range of critical values of t, so we have insufficient evidence to reject our null hypothesis as it will not fall in the rejection region.
Therefore, we conclude that there is no difference in potential mean sales per market in Region 1 and 2.
The numbers of words defined on randomly selected pages from a dictionary are shown below. Find the mean, median, mode of the listed numbers. 30 31 64 59 57 33 54 77 56 41 What is the mean? Select the correct choice below and ,if necessary ,fill in the answer box within your choice.(around to one decimal place as needed)
Answer:
30 31 64 59 58 33 54 77 56 41 (arrange it)
30 31 33 41 54 56 58 59 64 77 (done!)
Mean: Find the number in the middle (54+56)/2= 110/2 = 55
Mode: None
Mean: (30+31+33+41+54+56+58+59+64+77)/10=503/10= 50,3
Given v(x) = g(x) (3/2*x^4 + 4x – 1), find v'(2).
Answer:
Step-by-step explanation:
Given that v(x) = g(x)×(3/2*x^4+4x-1)
Let's find V'(2)
V(x) is a product of two functions
● V'(x) = g'(x)×(3/2*x^4+4x-1)+ g(x) ×(3/2*x^4+4x-1)
We are interested in V'(2) so we will replace x by 2 in the expression above.
g'(2) can be deduced from the graph.
● g'(2) is equal to the slope of the tangent line in 2.
● let m be that slope .
● g'(2) = m =>g'(2) = rise /run
● g'(2) = 2/1 =2
We've run 1 square to the right and rised 2 squares up to reach g(2)
g(2) is -1 as shown in the graph.
■■■■■■■■■■■■■■■■■■■■■■■■■■
Let's derivate the second function.
Let h(x) be that function
● h(x) = 3/2*x^4 +4x-1
● h'(x) = 3/2*4*x^3 + 4
● h'(x) = 6x^3 +4
Let's calculate h'(2)
● h'(2) = 6 × 2^3 + 4
● h'(2) = 52
Let's calculate h(2)
●h(2) = 3/2*2^4 + 4×2 -1
●h(2)= 31
■■■■■■■■■■■■■■■■■■■■■■■■■■
Replace now everything with its value to find V'(2)
● V'(2) = g'(2)×h(2) + g(2)× h'(2)
● V'(2)= 2×31 + (-1)×52
●V'(2) = 61 -52
●V'(2)= 9
Consider a normal population with a mean of 10 and a variance of 4. Find P(x < 6)
Answer: .0228
Step-by-step explanation: z = (6 − 10)/√4 = −2
P(X < 6) = .0228
the temperature at which water freezes on the celsius scale is 0 degrees C. It freezes at 32 degrees F on the Fahrenheit scale, write opposites fo these two numbers as integers.
Answer:
If we have an integer number N, the opposite of N will be:
-1*N = -N.
Then, the opposite of 0°C is:
-1*0°C = 0°C.
The number 0 is it's own opposite.
And for 32F, the opposite is:
-1*32F = -32F
So, while the numbers 0°C and 32F physically represent the same thing (the same temperature), mathematically, they behave differently.
The hypotenuse of a right triangle is 14 in. If the base
of the triangle is 2 inches determine the
length of the remaining side.
14 in
Х
2 in
O A &
B. 318
O c. 8v3
OD. 112
Answer:
13.85
Step-by-step explanation:
U use the pythagorean theorem
So 2^2 + x^2 = 14^2
Simplify the equation: 4+x^2=196
--> x^2=192
--> x=13.85
-Hope this helps :)
9514 1404 393
Answer:
c. 8√3
Step-by-step explanation:
The Pythagorean theorem applies.
14² = s² + 2²
s = √(14² -2²) = √192 = 8√3
The length of the remaining side is 8√3.
Lynn estimates roof jon 1500,bo estimates 2400. What's the ratio to lynn to bo
Answer:
5:8
Step-by-step explanation:
If I understand your question correctly, we have 1500/2400=15/24=5/8, so we have Lynn:Bo is 5:8, however, in the future please be more clear.
What is "estimates roof jon"? And, instead of saying "ratio to lynn to bo" say "What is the ratio of the estimates?" or whatever you're asking. If this answer is wrong, you only have yourself to blame.
find the alternateof AHG
Answer:
angle HGD
Step-by-step explanation:
alternate angles are in Z position
A buoy floating in the sea is bobbing in simple harmonic motion with amplitude 13 in and period 0.25 seconds. Its displacement d from sea level at time t=0 seconds is 0in, and initially it moves downward. (Note that downward is the negative direction.)Required:Give the equation modeling the displacement d as a function of time t.
Answer:
The equation is [tex]x(t) = -13 cos (8 \pi t )[/tex]
Step-by-step explanation:
From the question we are told that
The amplitude is [tex]A = 13 \ in[/tex]
The period is [tex]T = 0.25[/tex]
Generally the displacement function for a simple harmonic motion is mathematically represented as
[tex]x(t) = A cos (wt )[/tex]
Here [tex]w[/tex] is the angular frequency which is mathematically represented as
[tex]w = \frac{2 \pi }{T}[/tex]
substituting values
[tex]w = \frac{2 \pi }{ 0.25}[/tex]
[tex]w = 8\pi[/tex]
Given that at t = 0 the displacement is equal to 0 it means that there is no phase shift and also we are told that it is initially moving downward which implies that its Amplitude is [tex]A = -13\ in[/tex]
So the equation modeling the displacement d as a function of time t is mathematically represented as
[tex]x(t) = -13 cos (8 \pi t )[/tex]
A schoolteacher would like to know whether or not toothpaste brands are used differentially in her classroom (in other words, is one brand preferred over the others?). She asks her students to report which of three brands they use: Crest, Colgate, or Aquafresh. Below are the numbers of students who use each type of toothpaste (notice there are 45 students total in her class). Test her hypothesis using an alpha level of .05.
Crest Colgate Aquafresh
24 13 8
a. What test is appropriate for this analysis?
b. State the null hypothesis:
c. State the alternative hypothesis:
d. Find the critical value:
e. Calculate the test statistic:
f. Make a decision:
Answer:
Step-by-step explanation:
a. What test is appropriate for this analysis?
A Chi-square test of independence is appropriate for this analysis because it is used to compare two variables or testing relationship on categorical variables.
b. State the null hypothesis:
The null hypothesis is the default hypothesis
[tex]\mathtt{H_o:}[/tex] There is no particular preference for any brand of toothpaste among students.
c. State the alternative hypothesis:
The alternative hypothesis is the research hypothesis which comes in place to challenge the validity of the null hypothesis.
[tex]\mathtt{H_a:}[/tex] There is particular preference for brands of toothpaste among students.
d. Find the critical value:
degree of freedom = n-1
degree of freedom = 3 - 1
degree of freedom = 2
At the level of significance ∝ = 0.05
The confidence interval = 0.95 and degree of freedom = 2, the critical value from the chi-square distribution table = 5.991
e. Calculate the test statistic:
Using the chi square test statistics; we have the following:
Crest Colgate Aquafresh Total
24 13 8 45
Since we have three brands. Then, for each brand, the expected value
= Total /3
= 45/3
=15
Thus:
Chi -square [tex]\mathtt{X^2 = \dfrac{(observed \ value - expected \ value)^2}{expected \ value}}[/tex]
[tex]\mathtt{X^2 = \dfrac{(24 - 15)^2}{15} + \dfrac{(13 - 15)^2}{15} + \dfrac{(8 - 15)^2}{15} }[/tex]
[tex]\mathtt{X^2 = \dfrac{81}{15} + \dfrac{4}{15} + \dfrac{49}{15} }[/tex]
[tex]\mathtt{X^2 = \dfrac{81+4+49}{15}}[/tex]
[tex]\mathtt{X^2 = \dfrac{134}{15}}[/tex]
[tex]\mathtt{X^2 =8.93 }[/tex]
f. Make a decision:
Since the chi-square value is greater than the critical value , we reject the null hypothesis and conclude that the students have particular preference for brands of toothpaste.
Suppose that three computer boards in a production run of forty are defective. A sample of five is to be selected to be checked for defects.
a. How many different samples can be chosen?
b. How many samples will contain at least one defective board?
c. What is the probability that a randomly chosen sample of five contains at least one defective board?
Answer:
(a) 658,008 different samples can be chosen.
(b) 222,111 samples will contain at least one defective board.
(c) The probability that a randomly chosen sample of five contains at least one defective board is 0.34.
Step-by-step explanation:
We are given that three computer boards in a production run of forty are defective. A sample of five is to be selected to be checked for defects.
(a) To find how many different samples can be chosen, we will use a combination formula here because the order of selecting a sample of 5 from the production run of 40 doesn't matter.
Here, n = total sample = 40 and r = selected sample = 5
So, the combination formula is; [tex]^{n}C_r= \frac{n!}{r! \times (n-r)!}[/tex]
[tex]^{40}C_5= \frac{40!}{5! \times (40-5)!}[/tex]
[tex]^{40}C_5= \frac{40!}{5! \times 35!}[/tex]
[tex]^{40}C_5[/tex] = 658,008 ways
So, 658,008 different samples can be chosen.
(b) To find how many samples will contain at least one defective board, we will first find how many samples will contain no or 0 defective board.
For this also, we will use a combination where n = 40 - 3 = 37 non-defective computer board and a sample of r = 5 computer boards.
So, [tex]^{n}C_r= \frac{n!}{r! \times (n-r)!}[/tex]
[tex]^{37}C_5= \frac{37!}{5! \times (37-5)!}[/tex]
[tex]^{37}C_5= \frac{37!}{5! \times 32!}[/tex]
[tex]^{37}C_5[/tex] = 435,897 ways
This means that 435,897 of the 658,008 samples will contain no defective board.
Now, the samples that will contain at least one defective board = Total samples - Samples that contain no defective board
= 658,008- 435, 897
= 222,111
(c) The probability that a randomly chosen sample of five contains at least one defective board is given by;
Required Probability = [tex]\frac{222,111}{658,008}[/tex]
= 0.34 or 34%