how do i answer these?
Atrucking company determined that the distance traveled per truck per year is normally distributed, with a mean of 50 thousand miles and a standard deviation of 12 thousand miles. Complete parts (a) through (0) below. a. What proportion of trucks can be expected to travel between 36 and 50 thousand miles in a year? The proportion of trucks that can be expected to travel between 36 and 50 thousand miles in a year is D. (Round to four decimal places as needed.) A set of final examination grades in an introductory statistics course is normally distributed, with a mean of 71 and a standard deviation of 7. Complete parts (a) through (d). a. What is the probability that a student scored below 80 on this exam? The probability that a student scored below 80 is (Round to four decimal places as needed.)A study indicates that 18- to 24- year olds spend a mean of 125 minutes watching video on their smartphones per month. Assume that the amount of time watching video on a smartphone per month is normally distributed and that the standard deviation is 15 minutes. Complete parts (a) through (d) below. a. What is the probability that an 18- to 24-year-old spends less than 105 minutes watching video on his or her smartphone per month? The probability that an 18- to 24-year-old spends less than 105 minutes watching video on his or her smartphone per month is D. (Round to four decimal places as needed.) A survey found that women's heights are normally distributed with mean 62.7 in. and standard deviation 2.6 in. The survey also found that men's heights are normally distributed with mean 69.8 in. and standard deviation 3.2 in. Consider an executive jet that seats six with a doorway height of 56.2 in. Complete parts (a) through (c) below. a. What percentage of adult men can t through the door without bending? The percentage of men who can t without bending is |:|%. (Round to two decimal places as needed.) The lengths of pregnancies are normally distributed with a mean of 268 days and a standard deviation of 15 days. a. Find the probability of a pregnancy lasting 308 days or longer. b. If the length of pregnancy is in the lowest 2%, then the baby is premature. Find the length that separates premature babies from those who are not premature. Click to view [@ge 1 of the table. Click to view page 2 of the table. a. The probability that a pregnancy will last 308 days or longer is D. (Round to four decimal places as needed.) Given a standardized normal distribution (with a mean of 0 and a standard deviation of 1}, complete parts (a) through (d). a Click here to view page 1 of the cumulative standardized normal distribution table. a Click here to view page 2 of the cumulative standardized normal distribution table. a. What is the probability that Z is less than 1.56? The probability that Z is less than 1.56 is D. (Round to four decimal places as needed.) Given a standardized normal distribution (with a mean of 0 and a standard deviation of 1), determine the following probabilities. a. P(Z > 1.04) b. P(Z 1.04) = D (Round to four decimal places as needed.)
