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10. Hypothesis Testing for Two Samples - Part 2 of 2!
10. Hypothesis Testing for Two Samples / Two Means - Known Variance / Problem 3
Problem 3

A company compares the mean monthly sales (in units) of two sales teams.
Team X: xˉ1=155 \(\bar{x}\)_1 = 155 , σ1=15 \(\sigma\)_1 = 15 , n1=30 n_1 = 30 .
Team Y: xˉ2=148 \(\bar{x}\)_2 = 148 , σ2=12 \(\sigma\)_2 = 12 , n2=35 n_2 = 35 .
Construct a 90%90\% confidence interval for the difference in mean sales (μ1−μ2 \(\mu\)_1 - \(\mu\)_2 ).