You Wish to Compute a Confidence Interval For $\mu _ { 1 } - \mu _ { 2 }$

Multiple Choice

You wish to compute a confidence interval for $\mu _ { 1 } - \mu _ { 2 }$
For two normally distributed populations.Independent random samples of are taken from each population.The relevant sample statistics are n₁ = 10,n₂ = 8,s₁ = 5,and s₂= 7.If we assume the population variances are equal,give a pooled estimate of this common variance.

A) 28.2
B) 29.7
C) 41.8
D) 35.5
E) 42.3