QUESTION 2

1. Suppose we were to gather a random sample of 14 observations from a population and wished to calculate a 95% confidence interval for the mean,, in the case where the population standard deviation,, is unknown. Enter the value from the Student'stdistribution that we would use, to three decimal places.

QUESTION 3

1. Suppose we were to gather a random sample of 19 observations from a population and wished to calculate a 99% confidence interval for the mean,, in the case where the population standard deviation,, is unknown. Enter the value from the Student'stdistribution that we would use, to three decimal places.

QUESTION 5

1. All else being equal,when computing a confidence interval,as the sample size,n,increases,the margin of error_______
2. increases.
3. stays the same.
4. decreases.
5. always doubles.

QUESTION 6

A random sample of 51 undergraduate statistics students resulted in a sample mean age of 24.8 years, with a sample standard deviation of 2.5 years. Find theupper boundof the99%confidence interval for the true mean age, to one decimal place.

QUESTION 7

A random sample of 46 undergraduate statistics students resulted in a sample mean age of 24.8 years, with a sample standard deviation of 4.7 years. Find thelower boundof the 90% confidence interval for the true mean age, to one decimal place.

QUESTION 8

1. Dr. Mack Lemore, an expert in consumer behavior, wants to estimate the average amount of money that people spend in thrift shops. He takes a small sample of 8 individuals and asks them to report how much money they had in their pockets the last time they went shopping at a thrift store. Here are the data:

24, 44, 18, 26, 30, 29, 28, 27.

Find theupper boundof a 95% confidence interval for the true mean amount of money individuals carry with them to thrift stores, to two decimal places.Take all calculations toward the final answer to three decimal places.

QUESTION 9

1. A policy manager at an insurance company is interested in reducing the time it takes to approve new applications for whole life insurance policies. The approval process involves several steps, including an underwriting review of the policy, a medical background check and, if needed, additional information from the applicant based on the results of that examination, and final preparation of the documentation for delivery. The manager has obtained the following data on application processing time, in calendar days:

n2743.9s25.3

Using this information, she finds that the90%confidence interval for the true mean processing time is betweenand.Enter your answers to (1) decimal place.

QUESTION 10

1. TheWhole Foods Market grocery store labels its express checkout lanes with a sign saying"10-ish items or less", indicating that customers don't need to worry about havingexactly10 items to use the lane as is the case with other stores. But it is important to make sure that the express lanes don't accept customers with too many items.

The manager of Whole Foods stores in a particular region of the U.S. has been asked to estimate the mean number of items that customers going through the "10-ish items or less" line actually have. She decides to start with a small study. She takes a sample of 86 sales receipts from the "10-ish" lines in a particular store over a few days and finds that the sample mean is 9 items, with a standard deviation of 1.5 items.Calculate a95%confidence interval for the true mean number of items that customers bring through the "10-ish items or less" lines.Take all calculations to three (3) decimal places, and report your answers to one (1) decimal place.

Lower Bound:

Upper Bound:

QUESTION 11

A manufacturer of smartphones is interested in designing a new phone around the way a typical customer would use it. One of the most important characteristics for any smartphone is battery life since every activity on a smartphone draws power from the battery in some way. This is especially true for those who use their phones heavily for texting, social media, gaming, etc.

In a marketing research survey, the manufacturer asked a random sample of 25 smartphone owners who consider themselves "heavy users" to run an app on their phone that would record the time the phone is used for various activities (but, for privacy reasons, not record what that activity was).

The company decides to first examine the total minutes used in all activities. The sample mean number of minutes of total use from the 25 users was 118.2, with a standard deviation of 25.8 minutes. Find theupper boundof a 90% confidence interval for the true mean total time that smartphones are used by the population of "heavy users" to one decimal place.Take all calculations toward the answer to three (3) decimal places.

QUESTION 12

1. Dr. Mack Lemore, an expert in consumer behavior, wants to estimate the average amount of money that people spend in thrift shops. He takes a small sample of 8 individuals and asks them to report how much money they had in their pockets the last time they went shopping at a thrift store. Here are the data:

10.13,35.71,10.11,28.45,34.05,25.43,23.07,16.01.

Find thelower boundof a 98% confidence interval for the true mean amount of money individuals carry with them to thrift stores, to two decimal places.Take all calculations toward the final answer to three decimal places.

QUESTION 12

1. Put the four steps of the general hypothesis testing procedure in order.

Specify the hypothesis

Determine the rejectionregion (or calculate the p-value)

Make aconclusion

Calculate the test statistics

QUESTION 14

1. How does hypothesis testing differ from constructing confidence intervals, in general?Read carefully.

A. A hypothesis test examines the evidence in the data for a specified value or "guess" of the parameter chosen by the researcher, with the probability of making a Type I error equal to. A confidence interval gives a range of "reasonable" values for a parameter, and therefore is never wrong.

B. A hypothesis test examines the evidence in the data for aspecified value or "guess" of the parameter chosen by the researcher, while a confidenceinterval gives a range of "reasonable" values for the parameter based on the data.

C. A hypothesis test requires fewer assumptions than a confidence interval, and is also more accurate and informative for any choice of.

D. A hypothesis testgives a range of "reasonable" values for the parameter based on the data, while a confidence intervalexamines the evidence in the data for a specified value or "guess"of the parameter chosen by the researcher.

E. A hypothesis test leads to the right decision 50% of the time, while a confidence interval uses a method that is correctof the time (ex: 95% of the time).

QUESTION 15

1. A researcher wants to study sports-watching behavior of young men. In a random sample of young adult menbetween 20-30 years old, each man was asked how many minutes of sports he watched on TV daily. The researcher wishes to test whether the mean amount of television watched daily by young men is greater than 50 minutes.

Which of the following is the correct specification of thealternativehypothesis?