Statistics Memo

Taking a random sample from the population and calculating the mean from the data can pose some issues with the underlying population mean. Confidence intervals address this issue because it will provide a range of numbers that will likely contain the population parameter. Confidence intervals measure the probability that a population or data set will fall between two sets of values. The use of a confidence interval assists in providing an estimate by utilizing the data used in the collection process. When looking at the Major League Baseball statistics we will analyze the confidence interval of both wins and attendance from the data collection. This was done to aid team c in determining if there is a correlation between the number of wins that a Major League baseball team has and the effect on the attendance in the stands.

Team C has calculated the confidence interval for wins using 30 as the sample size, 56 as the standard deviation, and 81 as the mean.

Wins

Percent Lower Range Upper Range

99 75.65 86.35

95 77.12 84.88

90 77.74 85.26

Team C then calculated the confidence interval for attendance by using a sample size of 30, a standard deviation of 672,879, and the mean of 2,496,458.

Attendance

Percent Lower Range Upper Range

99 2,164,763 2,828,153

95 2,255,672 2,737,244

90 2,294,369 2,268,546

After analyzing the above data in combination with the extensive research that team c has performed over the past five weeks we have determined that there are several other factors that need to be analyzed in order to determine if wins truly does affect/correlate to attendance. Other outlying factors such as economic state of the city involved, climate, weather, and team promotions could all have a positive or negative effect on attendance even if the team is not winning. More extensive data collection will need to be done to make this determination. Therefore, the confidence intervals did not change the opinion of team c and further studies will need to be completed to determine how much of an affect that wins of a team has on how many fan show up to the ballpark.

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