4. (16 pts) The systolic blood pressure for a certain group of obese people has a mean of 142 and a standard deviation of 15.5. Assume that the variable is normally distributed.

(a) What percentage of people will have the blood pressure exceeding 150?

(b) A particular medicine is prescribed for those people with systolic blood pressure in the top 10%. What is the cuto value of the systolic blood pressure to receive this medicine?

(c) Find the interquartile range (IQR) of the distribution of systolic blood pressure.

(d) The systolic blood pressure for non-obese people is known to be distributed as N( = 125, = 10). What percent of non-obese people have their systolic blood pressure higher than average of systolic blood pressure for obese people?