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)