(Inference about Comparing two Populations): Exercise 13.8
13.8 Xr13-08 A men’s softball league is experimenting with a yellow baseball that is easier to see during night games. One way to judge the effectiveness is to count the number of errors. In a preliminary experiment, the yellow baseball was used in 10 games and the traditional white baseball was used in another 10 games. The number of errors in each game was recorded and is listed here. Can we infer that there are fewer errors on average when the yellow ball is used?
(Chi Square Tests): Exercise 15.48
15.48 Xr15-48 Every week the Florida Lottery draws six numbers between 1 and 49. Lottery ticket buyers are naturally interested in whether certain numbers are drawn more frequently than others. To assist players, the Sun-Sentinel publishes the number of times each of the 49 numbers has been drawn in the past 52 weeks. The numbers and the frequency with which each occurred were recorded. (These data are from the Sunday, January 5, 1997, edition.)
a. If the numbers are drawn from a uniform distribution, what is the expected frequency for each number?
b. Can we infer that the data were not generated from a uniform distribution?