Americans spend over $30 billion annually on a variety of weight loss products and services. in a study of retention rates of those using the rewards program at jenny craig in 2005, it was found that about 18% of those who began the program dropped out in the first four weeks.10 assume we have a random sample of 300 people beginning the program.
(a)what is the mean number of people who would drop out of the rewards program within four weeks in a sample of this size? what is the standard deviation?
(b)what is the approximate probability that at least 235 people in the sample will still be in the rewards program after the first four weeks?

There are two major tests of readiness for college: the act and the sat. act scores are reported on a scale from 1 to 36. the distribution of act scores in recent years has been roughly normal with mean µ = 20.9 and standard deviation s = 4.8. sat scores are reported on a scale from 400 to 1600. sat scores have been roughly normal with mean µ = 1026 and standard deviation s = 209. reports on a student's act or sat usually give the percentile as well as the actual score. the percentile is just the cumulative proportion stated as a percent: the percent of all scores that were lower than this one. tanya scores 1260 on the sat. what is her percentile (± 1)?