Hypothesis test for one population mean
1. Agriculture books. The R.R Bowker Company collects information on the retail prices of books and publishes the data in the Bowker annual library and book trade almanac. In 2005, the mean retail price of agriculture books was $ 57.61.This year's retail prices for 28 randomly selected agriculture books are shown in the following table:
59.54 67.70 57.10 46.11 46.86 62.87 66.40
52.08 37.67 50.47 60.42 38.14 58.21 47.35
50.45 71.03 48.14 66.18 59.36 41.63 53.66
49.95 59.08 58.04 46.65 66.76 50.61 66.68
At the 10% significance level, do the data provide sufficient evidence to conclude that this year's mean retail price of agriculture books has changed from the 2005 mean? Assume that the population standard deviation of prices for this year's agriculture books is $8.45. (Note: the sum of data is $1539.14)


Hypothesis test for one population mean when σ is unknown
1. Cardiovascular hospitalization. From the Florida state center for health statistics report, women and cardiovascular disease hospitalizations, we found that, for cardiovascular hospitalizations, the mean age of women is 71.9 years. At one hospital, a random sample of 20 of its female cardiovascular patients had the following ages, in years.

75.9 83.7 87.3 74.5 82.5
78.2 76.1 52.8 56.4 53.8
88.2 78.9 81.7 54.4 52.7
58.9 97.6 65.8 86.4 72.4