Assignment:
Question 1. Suppose you have drawn a simple random sample of 10 students from a college campus and recorded how many hours each student surfed the internet during the first week of February, 2010.
Results:
Student # 1 2 3 4 5 6 7 8 9 10
Hours of Internet Surfing 9 12 4 10 5 18 8 12 6 6
For this sample, compute ∑ Xi, the sample average (X-bar), ∑ (Xi – X-bar)2, and the sample standard deviation (s).
Question 2. Suppose the annual snowfall in a city is normally distributed with a mean of 80 inches and a standard deviation of 25 inches.
Find the probability that in a given year, snowfall in the city would be between 60 and 100 inches (that is, within ± 20 of μ = 80).
Question 3. Let X denote the amount of money an SU student spends on books in a year. Assume that population mean (μ) of X is $800, and the population standard deviation (σ) of X is $125. Suppose you have drawn a simple random sample of size 400 from the SU student population. Compute the probability that the sample mean (X) is between $790 and $810.
Question 4. Suppose 20% of SU students own Apple computers, that is, π = 0.2. You have drawn a simple random sample of size 400 from this population. Let p denote the proportion of the sample that own Apple computers. Compute the probability that for your sample of 400 students, p will fall between .18 to .22 (i.e., within ±.02 of π = .2).