Given a sphere with a diameter of 8 cm , find its volume to the nearest whole number

What is the standard deviation of the following data set rounded to the nearest tenth? 3, 17, 18, 15, 12, 21, 9

Awoman has 14 different shirts: 10 white shirts and 4 red shirts. if she randomly chooses 2 shirts to take with her on vacation, then what is the probability that she will choose two white shirts? show your answer in fraction and percent, round to the nearest whole percent.

What is the length of the midsegment of a trapezoid with bases of length 15 and 25 ?