2) The following data represent the number of passengers per flight in a random sample of 20 flights from Vienna, Austria, to Cluj-Napoca, Romania, with a new airline: 83 70 96 74 28 63 64 94 37 95 48 80 52 48 52 38 47 79 65 25 a) Find a 99% confidence interval for the mean number of passengers per flight. b) Find a 95% confidence interval for the population standard deviation.

The following sample of 16 measurements was selected from a population that is approximately normally distributed.Construct a 90% confidence interval for the population mean.

Fifteen randomly selected college students were asked to state the number of hours they slept the night before. The resulting data are: 6 16 7 8 7 796 3 11 9 15 4 7 9 a) Find the mean. b) Find the median. c) Find the standard deviation. d) According to Chebysev's Theorem, at least 75% of the times will fall between what two amounts? Is the theorem accurate for this set of data? Why of Why not? e) Are any of the reported hours "unusually" high? Are any of the reported hours unusually low?

2. University researchers claim that the average enrollment at four-year colleges is higher than two-year community colleges. Two surveys are undertaken at 35 four-year universities and 35 two-year colleges. The mean enrollment at the four-year institutions was 5,466 with a standard deviation of 8,191. The average enrollment at the two-year schools was 5,068 with a standard deviation of 4,777. Using a 95% confidence level, are the findings of the surveys consistent with the university researchers’ claim? 2. Does the null hypothesis reject H0 or fail to reject H0?