Question

Expedia would like to test the hypothesis that the average round-trip airfare between Philadelphia and Paris is higher for a flight originating in Philadelphia when compared to a flight originating in Paris. The following data summarizes the sample statistics for round-trip flights originating in both cities. Assume that the population variances are equal.

Originating City
Philadelphia Paris
Sample mean $1,240 $1,060
Sample size 15 19
Sample standard
deviation $270 $240
If Population 1 is defined as flights originating in Philadelphia and Population 2 is defined as flights originating in Paris, the degrees of freedom for this hypothesis test are _____
(a) 33
(b) 32
(c) 34
(d) 28

Answer 1

(b) 32

Explanation:

From the information given :

sample mean of Philadelphia μ₁ = $1240

Sample size of Philadelphia n₁ = 15

Sample Standard deviation σ₁ = $270

sample mean of Paris μ₂ = $1,060

Sample size of Paris n₂ = 19

Sample Standard deviation of Paris σ₂ = $240

If Population 1 is defined as flights originating in Philadelphia and Population 2 is defined as flights originating in Paris;

the degrees of freedom for this hypothesis test can be calculated as;

degree of freedom df = n - 1

degree of freedom for both hypothesis test = (n₁ - 1 + n₂ -1)

degree of freedom for both hypothesis test = (n₁ + n₂ - 2)

degree of freedom for both hypothesis test = ( 15 + 19 - 2)

degree of freedom for both hypothesis test are 32