Suppose that the average number of Facebook friends users have is normally distributed with a mean of 129 and a standard deviation of about 53. Assume forty-four individuals are randomly chosen. Answer the following questions. Round all answers to 4 decimal places where possible. What is the distribution of ¯xx¯? ¯xx¯ ~ N(,) For the group of 44, find the probability that the average number of friends is less than 119.  Find the first quartile for the average number of Facebook friends.

A standardized​ exam's scores are normally distributed. In a recent​ year, the mean test score was 1544 and the standard deviation was 314.The test scores of four students selected at random are 1940​, 1290​, 2250​,and 1420.Find the​ z-scores that correspond to each value and determine whether any of the values are unusual. ​(Round to 2 decimal places as​ needed.)

Jeremiah earned a score of 530 on Exam A that had a mean of 450 and a standard deviation of 40. He is about to take Exam B that has a mean of 63 and a standard deviation of 20. How well must Jeremiah score on Exam B in order to do equivalently well as he did on Exam A? Assume that scores on each exam are normally distributed.

Suppose that a category of world class runners are known to run a marathon (26 miles) in an average of 146 minutes with a standard deviation of 13minutes. Consider 49 of the races.Let X = the average of the 49 races. Find the 60th percentile for the average of these 49 marathons. (Round your answer to two decimal places.)min

The average resting heart rate for a normal adult is around 80 beats per minutes. A randomly selected group of 16 people who live in SF was taken and it was found that their average resting heart rate is 71.3 beats per minute. Assume that the standard deviation of the resting heart rate for any normal adult is 18 beats per minute. Test the claim that the average resting heart rate for people who live in SF is less than 80 beats per minute. Round your answer to the nearest tenth of a BPM For credit, the hypothesis test must contain: 1) Claim in terms of the appropriate parameter (e.g. μ = 4.5 m i l e s)  2) Null and alternative hypothesis 3) Sample evidence used 4) Test stat (z or t) , p-value and direction of test. (right, left or two tailed)  5) Whether you rejected or failed to reject the null hypothesis.  6) Conclusion telling us what the test concluded about your original claim.

Assume that the mean height of men in the United States is 70 inches, with a standard deviation of 3 inches.  A particular man is 80 inches tall.  Find the z-score of his height.  (Round to two decimal places.)

Suppose that the average number of Facebook friends users have is normally distributed with a mean of 136 and a standard deviation of about 45. Assume forty-two individuals are randomly chosen. Answer the following questions. Round all answers to 4 decimal places where possible.   Find the third quartile for the average number of Facebook friends

The ponderal index is a measure of overall size similar to a body mass index. The ponderal index of full term newborns follows a normal distribution with a mean of 2.4 kg/m3 and a standard deviation of 0.45 kg/m³. What percentage of full term newborns have a ponderal index greater than 2.5 kg/m³? Use Table 3 to obtain your answer. If necessary, round your final answer to 2 places after the decimal. Do not enter the % symbol, just the number representing the percent.

he average amount of time boys and girls  spend playing sports each week is believed to be the same. A sample of equal size n is taken from boys and girls , the mean of the boys is 29 hours  with standard deviation 4  hours and the mean of the girls  is 27 hours with standard deviation 3 hours Both populations have a normal distribution. The calculated value is  1.2       n =

Suppose that the average number of Facebook friends users have is normally distributed with a mean of 112 and a standard deviation of about 48. Assume forty-six individuals are randomly chosen. Answer the following questions. Round all answers to 4 decimal places where possible. 1. the group of 46, find the probability that the average number of friends is more than 123. 2. Find the first quartile for the average number of Facebook friends.