Travelocity would like to test if the standard deviation for roundtrip airfares between New York and London is less than $200. A random sample of 22 roundtrip airfares between New York and London had a standard deviation of $142. The degrees of freedom for this hypothesis test would be _______.
A)20
B)19
C)21
D)18

Question

Quizplus · Accepted Answer

The degrees of freedom for a hypothesis test involving the standard deviation or variance is calculated as the sample size minus one. Therefore, for a sample size of 22, the degrees of freedom would be 22 - 1 = 21.

Travelocity Would Like to Test If the Standard Deviation for Roundtrip