A school board is investigating two different academic programs. 20 students from each program were given the same exam, and the mean score was reported for Program A and Program B. A 95% T confidence interval for the difference in mean exam score (assuming equal variances) is reported as

(-10.524, -0.476)

1. What is the estimate of pooled standard deviation that was used to create this interval? (In the case of rounding errors, chose the closest option)

18.847

9.423

2.482

7.845

2. Had a (90%, 99%) confidence interval been constructed instead, the interval would be guaranteed to not cover 0.

Had a (90%, 99%) confidence interval been constructed instead, the interval might cover 0.