tbl 10

Maybe. 0.60 is a believable value of the population proportion based on the information above.

A confidence interval was used to estimate the proportion of statistics students that are females. A random sample of 72 statistics students generated the following 90% confidence interval: (0.443, 0.637). Based on the interval above, is the population proportion of females equal to 0.60?

$50.50 +/- $11.08

A major department store chain is interested in estimating the average amount its credit card customers spent on their first visit to the chain's new store in the mall. Fifteen credit card accounts were randomly sampled and analyzed with the following results: x-bar = $50.50 and sample variance = 400. Construct a 95% confidence interval for the average amount its credit card customers spent on their first visit to the chain's new store in the mall. Assume credit card expenditures on a first visit are ND.

We are 95% confident that the true proportion of all students receiving financial aid is between 0.52 and 0.66.

A university dean is interested in determining the proportion of students who receive some sort of financial aid. Rather than examine the records for all students, the dean randomly selects 200 students and finds that 118 of them are receiving financial aid. The 95% confidence interval for p is 0.59 +/- 0.07. Interpret this interval.

narrower for 90% confidence than for 95% confidence.

The width of a confidence interval estimate for a proportion will be

true

True or False: A random sample of 50 provides a sample mean of 31 with a standard deviation of s=14. The upper bound of a 90% confidence interval estimate of the population mean is 34.32.

False

True or False: A sample of 100 fuses from a very large shipment is found to have 10 that are defective. The 0.95 confidence interval would indicate that, for this shipment, the proportion of defective fuses is between 0 and 0.28.

false

True or False: In forming a 90% confidence interval for a population mean from a sample size of 22, the number of degrees of freedom from the t distribution equals 22.

true

True or False: The t distribution is used to develop a confidence interval estimate of the population mean when the population standard deviation is unknown.

It is used to construct confidence intervals for the population mean when the population standard deviation is known.

Which of the following is not true about the Student's t distribution?