StatCrunch Instructions: Two Independent Samples

Here is the StatCrunch output:

Hypothesis Test Results:

μ1: Mean of Population 1

μ2: Mean of Population 2

μ1 - μ2: Difference between two means

H0: μ1 - μ2 = 0

Ha: μ1 - μ2 > 0

(without pooled variances)

Difference Sample Mean Std. Err. DF T-Stat P-value
μ1 - μ2 4.9 0.92291766 1545.8916 5.3092494 <0.0001

As the output mentions, recall that we were testing

H0: μ1 - μ2 = 0

Ha: μ1 - μ2 > 0

and based on the small P-value, we rejected H0 and concluded that males 20 to 29 years old weigh more, on average, than males 75+ years old. It would be interesting to follow up this conclusion and estimate how much more males 20 to 29 years old weigh, on average. The 95% confidence interval does exactly that.