Please help me with these questions:

1)Need help with letter B

\f\ftical L values 38 2.712 2.429 2.024 1.686 39 1.304 2.708 2.426 38 2.023 1.685 40 1.304 2.704 2.423 39 2.021 1.684 45 1,303 2.690 2.412 40 2.014 1.679 1.301 a/2 50 2.678 45 2.403 2.009 1.676 1.289 60 2. 680 50 2.390 2.000 1.671 70 2.648 1.296 2.381 1.994 1.667 1.294 80 2.639 70 2.374 1.990 1.684 1.282 Critical + value Critical tvdue 90 2.632 2.368 1.987 1.682 1.291 (negative) (positive) 100 2.626 90 2.364 1.984 1.680 200 1.290 2.601 100 2.345 1.972 1.653 1.286 200 300 2.592 2.339 1.968 1.650 1.284 300 400 2.588 2.336 1.966 1.649 1.284 400 500 2.586 2.334 1.965 1.648 1.283 500 1000 2.581 2.330 1.962 1.646 1.282 1000 2000 2.578 2.328 1.961 1.646 1.282 2000 Large 2.576 2.326 1.960 1.645 1.282 Large Degrees of Area In One Tall 0.005 Degrees of Freedom 0.01 0.025 0.05 0.10 Freedom.2.37 Salaries of 39 college graduates who took a statistics course in college have a mean, x, of $68,500. Assuming a standard deviation, , of $10,900, construct a 99% confidence interval for estimating the population mean . Click here to view a t distribution table. Click here to view page 1 of the standard normal distribution table. Click here to view page 2 of the standard normal distribution table. $