How do the number of cups of coffee that nurses drink during their shift differ between the day shift and night shift nurses? The probability distribution for the amount of coffee consumed for the two nursing shifts is provided in the table. Let D = the number of cups of coffee for a nurse on the day shift. Let N = the number of cups of coffee for a nurse on the night shift. Use the histograms and the table to compare the difference between the two nursing shifts and the amount of coffee consumed. The distribution of number of cups of coffee for the day shift is , while the distribution for the night shift is . The mean for the distribution of the day shift is the mean for the night shift. By looking at the standard deviations, we see that the variability for the day shift is the variability of the night shift.