Author:
Christine Farr

Question 1

A random sample of 60 teenagers revealed that teenagers received an average 2,272 text messages per month. Using this sample, what is the standard error of the mean assuming the population standard deviation is 953 text messages per month?

Question 2

A random sample of 60 teenagers revealed that teenagers received an average 2,272 text messages per month. Using this sample, what is the lower bound for a 90% confidence interval assuming the population standard deviation is 953 text messages per month?

Question 3

A random sample of 60 teenagers revealed that teenagers received an average 2,272 text messages per month. Using this sample, what is the upper bound for a 90% confidence interval assuming the population standard deviation is 953 text messages per month?

Question 4

A random sample of 60 teenagers revealed that teenagers received an average 2,272 text messages per month. Using this sample, what is the lower bound for a 99% confidence interval assuming the population standard deviation is 953 text messages per month?

Question 5

A random sample of 60 teenagers revealed that teenagers received an average 2,272 text messages per month. Using this sample, what is the upper bound for a 99% confidence interval assuming the population standard deviation is 953 text messages per month?

Question 6

Travelocity would like to estimate the current average domestic airfare. The following data show the airfares for 24 randomly selected tickets for travel within the United States:

$356 $275 $371 $384 $457 $326

$414 $367 $362 $286 $104 $136

$320 $244 $370 $215 $322 $409

$303 $489 $251 $361 $337 $265

Construct a 95% confidence interval with these data to estimate the average domestic airfare. What is the lower bound?

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