Question 1 (1 point)

For each of the following variables, identify the level of measurement (nominal, ordinal, interval, or ratio).
(I) Satisfaction level on a survey (e.g. very dissatisfied, satisfied, very satisfied, etc.)
(II) Year of high school graduation

Question 1 options:

Question 2 (1 point)

Choose the description which best describes the shape of this boxplot.

Question 2 options:

Question 3 (1 point)

The five-number summary for a dataset on Grade Point Average is given in the table below. Using this information, calculate the percent of values below 1.06.

Question 3 options:

Question 4 (1 point)

Suppose it is known that the mean and standard deviation of the scores on a statistics final are 74.45 and 5.75, respectively. Calculate an interval that is symmetric around the mean such that it contains approximately 95% of scores. Assume that the scores have a normal distribution.

Question 4 options:

A highway department is studying the relationship between traffic flow and speed. The following model has been hypothesized:

y = β₀ + β₁x + ε

where

• y = traffic flow in vehicles per hour
• x = vehicle speed in miles per hour.

The following data were collected during rush hour for six highways leading out of the city.

In working further with this problem, statisticians suggested the use of the following curvilinear estimated regression equation.

ŷ = b₀ + b₁x + b₂x²

(a)

Develop an estimated regression equation for the data of the form

ŷ = b₀ + b₁x + b₂x².

(Round b₀ to the nearest integer and b₁ to two decimal places and b₂ to three decimal places.)ŷ =

Find the value of the test statistic. (Round your answer to two decimal places.)

Find the p-value. (Round your answer to three decimal places.)

p-value =

Base on the model predict the traffic flow in vehicles per hour at a speed of 38 miles per hour. (Round your answer to two decimal places.)

vehicles per hour

Find the 90% confidence interval for the standard deviation of the lengths of pipes if a sample of 22 pipes has a standard deviation of 10.6 inches.

a. (8.3, 13.8)

b. (8.5, 13.3)

c. (8.5, 14.3 )

d. (8.1, 15.3)

How might you motivate what a sufficient statistic is? Find a sufficient statistic for the Poisson distribution with parameter lambda.

Allergic reactions to poison ivy can be miserable. Plant oils cause the reaction. Researchers at Allergy Institute did a study to determine the effects of washing the oil off within 5 minutes of exposure. A random sample of 1000 people with known allergies to poison ivy participated in the study. Oil from the poison ivy plant was rubbed on a patch of skin. For 500 of the subjects, it was washed off within 5 minutes. For the other 500 subjects, the oil was washed off after 5 minutes. The results are summarized in the following table.

Let's use the following notation for the various events: W = washing oil off within 5 minutes, A = washing oil off after 5 minutes, N = no reaction, M = mild reaction, S = strong reaction. Find the following probabilities for a person selected at random from this sample of 1000 subjects. (Use 3 decimal places.)

(e) P(N or M).

Are the events N = no reaction and M = mild reaction mutually exclusive? Explain.

No. P(N or M) ≠ 0.Yes. P(N and M) = 0.    Yes. P(N or M) = 0.No. P(N and M) ≠ 0.

(f) Are the events N = no reaction and W = washing oil off within 5 minutes independent? Explain.

Yes. P(N and W) = P(N) · P(W).Yes. P(N and W) ≠ P(N) · P(W).    No. P(N and W) = P(N) · P(W).No. P(N and W) ≠ P(N) · P(W).

A population is normally distributed with μ=300 and σ=20.

A. Find the probability that a value randomly selected from this population will have a value greater than 345

B. Find the probability that a value randomly selected from this population will have a value less than 295

C. Find the probability that a value randomly selected from this population will have a value between 295 and 345

Click the icon to view the standard normal table.

A. P( x > 345)= ______________ (round to four decimal places as needed)

B. P( x< 295)= ________________ (Round to four decimal places as needed)

C. P( 295 < x < 345)= ____________ (round to four decimal places as needed)

The method of tree ring dating gave the following years A.D. for an archaeological excavation site. Assume that the population of x values has an approximately normal distribution.

(a) Find a 90% confidence interval for the mean of all tree ring dates from this archaeological site. (Round your answers to the nearest whole number.)

How much does a sleeping bag cost? Let's say you want a sleeping bag that should keep you warm in temperatures from 20°F to 45°F. A random sample of prices ($) for sleeping bags in this temperature range is given below. Assume that the population of x values has an approximately normal distribution.

(b) Using the given data as representative of the population of prices of all summer sleeping bags, find a 90% confidence interval for the mean price μ of all summer sleeping bags. (Round your answers to two decimal places.)

How much do wild mountain lions weigh? Adult wild mountain lions (18 months or older) captured and released for the first time in the San Andres Mountains gave the following weights (pounds):

(c) Find a 75% confidence interval for the population average weight μ of all adult mountain lions in the specified region. (Round your answers to one decimal place.)

Do you want to own your own candy store? Wow! With some interest in running your own business and a decent credit rating, you can probably get a bank loan on startup costs for franchises such as Candy Express, The Fudge Company, Karmel Corn, and Rocky Mountain Chocolate Factory. Startup costs (in thousands of dollars) for a random sample of candy stores are given below. Assume that the population of x values has an approximately normal distribution.

(d) Find a 90% confidence interval for the population average startup costs μ for candy store franchises. (Round your answers to one decimal place.)

a.

Describe the Pooled variance assumption. How does it change the standard error? What impact does it have on a test statistic? What impact does it have on a p-value?

How do you justify making the assumption?

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b.

The above contingency table was created by asking a sample of people in a given area if they support a measure taken by the government.  

If The variables were independent how many Republicans in our sample would we expect to Support the measure proposed?

2.

ohn believes he randomly selects his choice in Rock Paper Scissors.  

His friend challenges him to record what he chooses over the next 3 months.  

Do a full hypothesis test to see if the data is truly balanced.  

Let x be a random variable that represents white blood cell count per cubic milliliter of whole blood. Assume that x has a distribution that is approximately normal, with mean μ = 6750 and estimated standard deviation σ = 2250. A test result of x < 3500 is an indication of leukopenia. This indicates bone marrow depression that may be the result of a viral infection.

(a) What is the probability that, on a single test, x is less than 3500? (Round your answer to four decimal places.)


(b) Suppose a doctor uses the average x for two tests taken about a week apart. What can we say about the probability distribution of x?

a. The probability distribution of x is not normal.

b. The probability distribution of x is approximately normal with μ_x = 6750 and σ_x = 1590.99.   

c. The probability distribution of x is approximately normal with μ_x = 6750 and σ_x = 2250.

d. The probability distribution of x is approximately normal with μ_x = 6750 and σ_x = 1125.00.

What is the probability of x < 3500? (Round your answer to four decimal places.)


(c) Repeat part (b) for n = 3 tests taken a week apart. (Round your answer to four decimal places.)


(d) Compare your answers to parts (a), (b), and (c). How did the probabilities change as n increased?

a. The probabilities stayed the same as n increased.

b. The probabilities increased as n increased.    

c. The probabilities decreased as n increased.

If a person had x < 3500 based on three tests, what conclusion would you draw as a doctor or a nurse?

a. It would be a common event for a person to have two or three tests below 3,500 purely by chance. The person probably has leukopenia.

b. It would be a common event for a person to have two or three tests below 3,500 purely by chance. The person probably does not have leukopenia.

c. It would be an extremely rare event for a person to have two or three tests below 3,500 purely by chance. The person probably has leukopenia.

d. It would be an extremely rare event for a person to have two or three tests below 3,500 purely by chance. The person probably does not have leukopenia.

Coal is carried from a mine in West Virginia to a power plant in New York in hopper cars on a long train.

The automatic hopper car loader is set to put 71 tons of coal into each car.

The actual weights of coal loaded into each car are normally distributed, with mean μ = 71 tons and standard deviation σ = 0.5 ton.

(a) What is the probability that one car chosen at random will have less than 70.5 tons of coal? (Round your answer to four decimal places.)


(b) What is the probability that 24 cars chosen at random will have a mean load weight x of less than 70.5 tons of coal? (Round your answer to four decimal places.)


(c) Suppose the weight of coal in one car was less than 70.5 tons. Would that fact make you suspect that the loader had slipped out of adjustment?

Yes or No   

Suppose the weight of coal in 24 cars selected at random had an average x of less than 70.5 tons. Would that fact make you suspect that the loader had slipped out of adjustment? Why?

a. Yes, the probability that this deviation is random is very small.

b. Yes, the probability that this deviation is random is very large.    

c. No, the probability that this deviation is random is very small.

d. No, the probability that this deviation is random is very large.

The marital status distribution of the U.S. male population, age 15 and older, is as shown below.

Suppose that a random sample of 400 U.S. young adult males, 18 to 24 years old, yielded the following frequency distribution. We are interested in whether this age group of males fits the distribution of the U.S. adult population at the 5% level. Calculate the frequency one would expect when surveying 400 people. Fill in the table below, rounding to two decimal places.

A. What are the degrees of freedom? (Enter an exact number as an integer, fraction, or decimal.)
B. State the distribution to use for the test.

C. What is the test statistic? (Round your answer to two decimal places.)
D. What is the p-value? (Round your answer to four decimal places.)
E. Alpha (Enter an exact number as an integer, fraction, or decimal.)
α =

The assets​ (in billions of​ dollars) of the four wealthiest people in a particular country are 37, 35, 31, 18. Assume that samples of size n=2 are randomly selected with replacement from this population of four values. a. After identifying the 16 different possible samples and finding the mean of each​ sample, construct a table representing the sampling distribution of the sample mean. In the​ table, values of the sample mean that are the same have been combined.

_

x probability

37

36

35

34

33

31

27.5

26.5

24.5

18

b. Compare the mean of the population to the mean of the sampling distribution of the sample mean.

Mean of population is? Sample mean is?

c. Do the sample means target the value of the population​ mean? In​ general, do sample means make good estimates of population​ means? Why or why​ not?

The sample means target/do not target the population mean. In​ general, sample means do/do not make good estimates of population means because the mean is an unbiased/ a biased estimator.

For a regression of test score (T) on the endogenous variable student-teacher ratio (R), Hoxby (2000) suggests using as an instrument the deviation of potential enrollment from its long-term trend (P), where "potential enrollment" means how many children of kindergarten age there are (whether or not they attend public school). Which of the following arguments would NOT support P as an instrument for R?

PLEASE PROVIDE EXPLANATION IN ANSWER

A software developer wants to know how many new computer games people buy each year. A sample of 164 people was taken to study their purchasing habits. Construct the 80% confidence interval for the mean number of computer games purchased each year if the sample mean was found to be 7.8. Assume that the population standard deviation is 1.5. Round your answers to one decimal place.

If a researcher found that there was a correlation of r = -0.67 between the number of siblings a person has and introversion, and the researcher sampled n = 30 people, what conclusions can you make about this relationship