Data were collected on annual personal time (in hours) taken by a random sample of 16 women and 20 men employed by a medium-sized company.The women took an average of 24.75 hours of personal time per year with a standard deviation of 2.84 hours.The men took an average of 20.5 hours of personal time per year with a standard deviation of 2.75 hours.The pooled estimate of the variance is ________________________ .
A)264.6715
B)2.790
C)7.785
D)12.998
E)None of the above.

Question

Quizplus · Accepted Answer

The pooled estimate of the variance is calculated using the formula: [(n1-1)s1^2 + (n2-1)s2^2] / (n1+n2-2). For this data, it is [(16-1)(2.84)^2 + (20-1)(2.75)^2] / (16+20-2) = 7.785.

Data Were Collected on Annual Personal Time (In Hours) Taken