To increase efficiency, officials at the Canadian Pacific Railway monitor several variables including train speed, cars on each train, and terminal dwell time. In addition, the type and amount of freight is carefully recorded for each train. The following table shows the number of carloads of grain mill products for 30 randomly selected weeks in 2011 and 2012.
a. Compute the summary statistics for these data, including the mean, median, variance, standard deviation and quartiles.
b. Construct a box plot for these data.
c. Describe the distribution. Identify any outliers.
d. Find the proportion of observations within one, two, and three standard deviations of the mean. Compare the results to the empirical rule.
e. Find the 90th percentile.