don't need work shown but please tell me which formulas used. Thank you.

15. Gravetter/Wallnau/Forzano, Essentials - Chapter 10 - End-of-chapter question 22 For each of the following, calculate the pooled variance and the estimated standard error for the sample mean difference. The first sample has n = 4 scores and a variance of $2 = 17, and the second sample has n = 8 scores and a variance of s? = 27. 5(MI - M2) = Now the sample variances are increased so that the first sample has n = 4 scores and a variance of s = 68, and the second sample has n = 8 scores and a variance of s? = 108. = 5(MI - M2) Comparing your answers for the preceding parts, how does increased variance influence the size of the estimated standard error? Increased variance the estimated standard error