The amount of time single men and women spend on housework i

The amount of time single men and women spend on housework is measured for 15 single women and 25 single men. For the women the mean was 7 hours/week with a standard deviation of 1.5. For the men the mean was 4.5 hours/week with a standard deviation of 1.1. What is the value of the pooled standard deviation for the difference in mean time spent on housework between single men and women?

The answer key says 1.26, but I keep getting 1.59.

Solution

Value Pooled variance S^2= (n1-1*s1^2 + n2-1*s2^2 )/(n1+n2-2)
S^2 = (14*2.25 + 24*1.21) / (40- 2 )
Pooled Variance = S^2 = 1.593

Whe you say Pooled standard deviation = Sqrt(S^2) = Sqrt(1.593) = 1.26

[ANSWER] S = 1.26