In a study of the length of time that students require to earn bachelor's degrees, 100 students are randomly selected and they are found to have a mean of 4.5 years and a standard deviation of 1.8 years. Construct a 90% confidence interval estimate of the population mean.

Select one:

a.(4.31, 4.69)

b.None of other answer is necessary true.

c.(3.86, 5.14)

d.(4.20, 4.80)

e.(4.01, 4.99)

For women aged 18-24, systolic blood pressures (in mm Hg) are normally distributed with a mean of 114.8 and a standard deviation of 13.1 (based on data from the National Health Survey). If 12 women in that age bracket are randomly selected, find the probability that their mean systolic blood pressure is between 110 and 115.

Select one:

a.44.56%

b.39.60%

c.None of other answers is necessary true.

d.41.89%

e.49.70%

Counting the number of points when rolling a single die. Denote by M the event of rolling a number at least 4 and N the event of rolling a number 3. Which of the following is true?

Select one:

a.M and N are mutually exclusive

b.M and N are simple events

c.none of the other answers is necessary true.

d.M and N are independent

e.M is the complement of N