The following portion of a confidence interval confidence interval output is bas
ID: 3355832 • Letter: T
Question
The following portion of a confidence interval confidence interval output is based on a sample of delivery times (in hours) of a package from Phoenix to New York on Federal Express and United Parcel Service.
Sample Summaries
FedExp
UPS
Sample Size
7
9
Sample Mean
30.000
20.000
Sample Std Dev
6.928
5.315
The degrees of freedom to conduct a hypothesis test about the equality of population means is:
8
14
15
16
None of the above
Sample Summaries
FedExp
UPS
Sample Size
7
9
Sample Mean
30.000
20.000
Sample Std Dev
6.928
5.315
Explanation / Answer
when population variances are equal
the value of |t | with (n1+n2-2) i.e 14 d.f
when population variances are unequal
the value of |t | with min (n1-1, n2-1) i.e 6 d.f
[ANSWER] 14
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