For a sample of 5 different years from the period 1960 through 1998, it is found that U.S. work stoppages involving at least 1000 workers occurred 268 times in one of these years, with 424, 235, 145, and 44 work stoppages in the other four.
a. Determine the mean, median, range, and midrange.
b. Calculate the mean absolute deviation.
c. Calculate the standard deviation and variance.