Exam 9: Testing the Difference Between Two Means, Two Variances, and Two Proportions

A recent survey reported that in a sample of 300 students who attend two-year colleges, 105 work at least 20 hours per week. Additionally, in a sample of 225 students attending private four-year universities, only 20 students work at least 20 hours per week. What is the test value for a test of the difference between these two population proportions?

Samples are independent when they are not related.

The formula of the test value to be used in a t test for dependent samples is ______________.

When comparing the means of samples from two normally distributed populations, if the samples are independent and the population variances are known, the z test can be used.

A car salesman claims that the variance of prices on convertibles is higher than the variance of prices on station wagons. The standard deviation of the list price on 16 convertibles is $6800 and the standard deviation on 24 station wagons is $3900. What should the test value be?

Use the following to answer questions Mauricio Cruz, a wine merchant for Cruz's Spirits Emporium, wants to determine if the average price of imported wine is less than the average price of domestic wine. He obtained the data shown in the table below. -What is the null hypothesis?

When subjects are matched according to one variable, the matching process does not eliminate the influence of other variables.

The critical value for a two-tailed F test is 2.65 when α = 0.05, the sample size from which the variance for the numerator was obtained is 10, and the sample size from which the variance for the denominator was obtained is 15.

The critical value for a right-tailed F test is 2.57 when α = 0.025, the degrees of freedom for the numerator are 15, and the degrees of freedom for the denominator are 20.

In the F distribution, values of F cannot be negative, because variances are always positive or zero.