Cell Phone Call Lengths The average local cell phone call length was reported to be 2.39 minutes. A random sample of 24 phone calls showed an average of 2.83 minutes in length with a standard deviation of 0.9 minutes. At =α0.01, can it be concluded that the average differs from the population average? Assume that the population is approximately normally distributed.   a. State the hypotheses and identify the claim H0=    (claim or not claim) H1=    (claim or not claim)

On the planet of Mercury, 4-year-olds average 3.1 hours a day unsupervised. Most of the unsupervised children live in rural areas, considered safe. Suppose that the standard deviation is 1.3 hours and the amount of time spent alone is normally distributed. We randomly survey one Mercurian 4-year-old living in a rural area. We are interested in the amount of time X the child spends alone per day. (Source: San Jose Mercury News) Round all answers to 4 decimal places where possible.a.  What is the distribution of X? X ~ Nb.  Find the probability that the child spends less than 3.4 hours per day unsupervised. c.  What percent of the children spend over 4.9 hours per day unsupervised. % (Round to 2 decimal places) d.  86% of all children spend at least how many hours per day unsupervised? hours

On the planet of Mercury, 4-year-olds average 3.2 hours a day unsupervised. Most of the unsupervised children live in rural areas, considered safe. Suppose that the standard deviation is 1.6 hours and the amount of time spent alone is normally distributed. We randomly survey one Mercurian 4-year-old living in a rural area. We are interested in the amount of time X the child spends alone per day. (Source: San Jose Mercury News) Round all answers to 4 decimal places where possible. a. What is the distribution of X? X - N( b. Find the probability that the child spends less than 2.3 hours per day unsupervised. c. What percent of the children spend over 4.8 hours per day unsupervised. % (Round to 2 decimal places) d. 63% of all children spend at least how many hours per day unsupervised? hours. Hint: Helpful videos: • Find a Probability [+] • Finding a Value Given a Probability [+1 Hint Question Help: 9 Message instructor Submit Question logi *2 *3 F7 F8 7. 8. W R T. U 24 33

On the planet of Mercury, 4-year-olds average 2.9 hours a day unsupervised. Most of the unsupervised children live in rural areas, considered safe. Suppose that the standard deviation is 1.4 hours and the amount of time spent alone is normally distributed. We randomly survey one Mercurian 4-year-old living in a rural area. We are interested in the amount of time X the child spends alone per day. (Source: San Jose Mercury News) Round all answers to 4 decimal places where possible.a.  What is the distribution of X? X ~ N(_______ ,______) I know that question a is (2.9,1.4) b.  Find the probability that the child spends less than 1.3 hours per day unsupervised. c.  What percent of the children spend over 3.4 hours per day unsupervised. % (Round to 2 decimal places) d.  82% of all children spend at least how many hours per day unsupervised? hours.   Please help me understand how to do the rest.