The results of sampling independent populations known to have unequal variances:

sample 1 from population 1

• mean 1000
• sample standard deviation 400
• sample size 50

sample 2 from population 2

• mean 1250
• sample standard deviation 500
• sample size 75

Test the claim population 1 mean < population 2 mean at = 0.01.

The DF of the test statistic and standard error of the sample statistic are: