Q. A group of 625 students has a mean age of 15.8 years with a standard deviation of 0.6 years. The ages are normally distributed. What is the probability that a randomly selected student is older than 16.5 years old but younger than 18.5 years?

The lengths of pregnancies are normally distributed with a mean of 266 days and a standard deviation of 15 days. a. In a letter to an advice​ column, a wife claimed to have given birth 307 days after a brief visit from her​ husband, who was working in another country. Find the probability of a pregnancy lasting 307 days or longer. What does the result​ suggest? b. If the length of pregnancy is in the lowest 3​%, then the baby is premature. Find the length that separates premature babies from those who are not considered premature.       a. The probability that a pregnancy will last 307 days or longer is enter your response here. ​(Round to four decimal places as​ needed.) What does the result​ suggest?     A. The result suggests that either a very rare event occurred or the husband is not the father.   B. The result suggests an uncommon but not significant event occurred.   C. The result suggests the event did not occur.   D. The result suggests that the…

According to a study done by UCB students, the height for Martian adult males is normally distributed with an average of 64 inches and a standard deviation of 2.3 inches. Suppose one Martian adult male is randomly chosen. Let X = height of the individual. Round all answers to 4 decimal places where possible. a. What is the distribution of X? X - N( b. Find the probability that the person is between 62 and 63.9 inches. c. The middle 40% of Martian heights lie between what two numbers? Low: inches High: inches

The length of the long-distance calls made by the employees of a certain company are normally distributed with a mean of 6.3 minutes and a standard deviation of 2.5 minutes. Find the probability that a call will last between 5 and 10 minutes. A. .3897     B. .1788.   C. .6290.    D. .6308

The lengths of pregnancies are normally distributed with a mean of 268days and a standard deviation of 15 days. a. Find the probability of a pregnancy lasting 309 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.   a. The probability that a pregnancy will last 309 days or longer is   ​(Round to four decimal places as​ needed.)   b. Babies who are born on or before____days are considered premature. ​   (Round to the nearest integer as​ needed.)

Assume that the sales of Teri’s Specialty Cakes has historically followed a normal distribution, with an average of 250 cakes per month, and a standard deviation of 15 cakes.a. What is the probability that the sales for cakes will be no more than 285 over the next month?b. What is the probability that the sales for the cakes will be no more than 230 cakes over the next month?c. What is the probability that the sales for the cakes will be between 245 and 265 over the next month?d. What number of cake demand can Teri reasonably assume with a confidence level of 95%?For a, b, c, and d, please write out your work for at least one of these problems. For all problems, explain your answers and sketch a plot (similar to the handouts and text).

The lengths of pregnancies are normally distributed with a mean of 268 days and a standard deviation of 15days. a. Find the probability of a pregnancy lasting 309 days or longer. b. If the length of pregnancy is in the lowest 3​%,then the baby is premature. Find the length that separates premature babies from those who are not premature.

CNNBC recently reported that the mean annual cost of auto insurance is 968 dollars. Assume the standard deviation is 259 dollars, and the cost is normally distributed. You take a simple random sample of 36 auto insurance policies. Round your answers to 4 decimal places. a. What is the distribution of X? X - N( 968 259 b. What is the distribution of ? T - N( 968 c. What is the probability that one randomly selected auto insurance is less than $1015? 43.1667 0.5720 d. a simple random sample of 36 auto insurance policies, find the probability that the average cost is less than $1015. 0,8619 e. For part d), is the assumption of normal necessary? O Yes No