i need correct solution of these problems

A study of the effects of smoking on sleep patterns is conducted. The measure observed is the time, in minutes, that it takes to fall asleep. These data are obtained: Smokers: 69.3 56.0 22.1 47.6 53.2 48.1 52.7 34.4 60.2 43.8 23.2 13.8 Nonsmokers: 28.6 25.1 26.4 34.9 29.8 28.4 38.5 30.2 30.6 31.8 41.6 21.1 36.0 37.9 13.9 (a) Find the sample mean for each group. (b) Find the sample standard deviation for each group. (c) Make a dot plot of the data sets A and B on the same line. (d) Comment on what kind of impact smoking appears to have on the time required to fall asleep.The following data represent the length of life in years, measured to the nearest tenth, of 30 similar fuel pumps: 2.0 3.0 03 3.3 1.3 0.4 0.2 6.0 5.5 6.5 02 23 1.5 4.0 5.9 18 4.7 0.7 4.5 0.3 1.5 0.5 2.5 5.0 1.0 6.0 5.6 6.0 1.2 0.2 (a) Construct a stem-and-leaf plot for the life in years of the fuel pumps, using the digit to the left of the decimal point as the stem for each observation. (b) Set up a relative frequency distribution. (c) Compute the sample mean, sample range, and sample standard deviation.\f\f\f\fReferring to Exercise 3.38, find (a) the marginal distribution of X; (b) the marginal distribution of Y Reference: Exercise 3.38: If the joint probability distribution of X and Yis given by f(x, y) = 30 for x = 0, 1, 2, 3; y = 0, 1, 2, find a) P(X 2, Y= 1); c) (c) P(X >Y):(d) P(X + Y = 4)