Standard deviation = $21,200. Standard deviation is calculated as the square root of the variance; variance is calculated as follows, where M is the mean and N is the total number of scores.
Determine the coefficient of skewness using Pearson's method. 0.041. This is calculated as Sk = 3( - ) / Sx where denotes mean, denotes median, and Sx denotes the sample standard deviation. A value < 0 means the distribution is positively skewed.
Question 3, Part 2: The annual incomes of officers of another firm similar to TMV Industries were also studied. The mean was $129,000 and the standard deviation $8,612. Compare the means and dispersions in the two firms.
The mean income of officers in the two firms is almost identical. However, the dispersion as measured by the higher standard deviation of the second firm indicates that its officers' incomes have a greater variation than TMV's officers.
Question 4: Determine the mean and the standard deviation of the following frequency distribution. Mean = 12.7; standard deviation = 5.2.
0 up to 5 2
5 up to 10 7
10 up to 15 12
15 up to 20 6
20 up to 25 3
Standard deviation calculated using a frequency table. (n.d.). Produced for Statistics
Canada. Retrieved May 15, 2006, from http://www.statcan.ca/english/edu/power/ch12/variance.htm#ex2.
Wikipedia.com. (n.d.). Variance; standard deviation; frequency distribution; coefficient of skewness; Pearson's method. Retrieved May 15,