Can u tell me what the answer is for this one

1. Given these test scores: 3. Score Find Frequency data 60 3 70 4 xx XXXX Yx 75 6 X t x X X X 80 f x X X 4 90 W 60 70 80 90 Find the following: a) mean 15 b) standard deviation to the nearest tenth c) What is the number of scores that fall within one standard deviation of the mean (X +10)? d) probability that a randomly selected score falls within one standard deviation of the mean