Lab 4 on Central Tendency and Variability
Below are estimated numbers of annual road traffic deaths for 12 countries based on data from
the World Health Organization (apps.who.int/gho/data/view.main.51310):
a. Did you attend class on Friday, 10/2? (5 pts)
b. Compute the mean and the median across these 12 data points (4pts).
c. Compute the range for these 12 data points (3pts).
d. Recalculate the statistics in part (b) and part (c) without the data point for the United
States. How are these statistics affected by including or excluding the United States? (4pts)
e. How might these numbers be affected by using traffic deaths per 100,000 people instead
of using the number of traffic deaths overall? (3pts)
f. Do you think that traffic deaths might vary by other personal or national characteristics?
Could these represent confounds? Please explain your response. (3pts)
Here are winning percentages for 11 baseball players for their best 4-year pitching
performances:
g. What are the mean and median of these scores? (2pts)
h. What are the sample variance and standard deviation of these scores? (3pt)
i. Compare the mean and the median. Does the differences between them suggest that the
data are skewed very much? Please explain your answer. (3pts)
