Hi everyone! Read through the material below, watch the videos, work on the Excel lecture and follow up with your instructor if you have questions.


Learning Outcomes.

  • Compute statistical parameters (mean, median, mode, average deviation, variance, and sample standard deviation)

Topic. This lesson covers: Measures of Central Location and Variability

WeBWorK. Sets 2.5, 2.6 & 2.7

Excel Lecture #3


The applied view

Watch the video measures of center.

  1. What variable is examined in comparing men and women workers at the beginning of the video?
  2. Would you describe the shape of the distribution of men’s weekly wages as symmetric, skewed to the left or skewed to the right?
  3. What is the most important difference between the distributions of weekly wages for men and for women?
  4. Would a few very large incomes pull the mean of a group of incomes up, down, or leave the mean unaffected?
  5. Would a few very large incomes pull the median of a group of incomes up, down, or leave the median unaffected?

Watch the video boxplots.

  1. What variable is used to compare different brands of hot dogs?
  2. What name do we give to the value for which one-quarter of the data values falls at or below it?
  3. What numbers make up a five-number summary?
  4. How do you calculate the interquartile range?
  5. Boxplots show that poultry hot dogs as a group differ from all-beef hot dogs. Compare the distribution of calories between the two types of hot dogs.

Watch the video standard deviation.

  1. In comparing monthly precipitation for Portland, Oregon, and Montreal, Canada, why was comparing the mean monthly precipitation rates insufficient?
  2. Why don’t we measure spread about the mean by simply averaging x − xbar , the deviations of individual data values from their mean?
  3. What did the standard deviation of four-week sales data tell you about the two Wahoo’s Taco locations, Manhattan Beach and South Coast Plaza?
  4. Can the standard deviation of a set of observations be s = −1.5 ? Explain.

Exit Ticket

What does a measure of central location represent? What are the three most common measures of central location? In your everyday life, when was the last time you encountered a measure of central location? What was it?