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.
- Compute statistical parameters (mean, median, mode, average deviation, variance, and sample standard deviation)
Topic. This lesson covers: Measures of Central Location and Variability
- Openstax Introductory Statistics:
- Introductory Statistics by Sheldon Ross, 3rd edition: Sections 3.2-3.5
- Statistics with Microsoft Excel by Beverly J. Dretzke, 5th ed., AVERAGE( : ), VARP( : ), STDEVP( : ), P. 36 – 45
WeBWorK. Sets 2.5, 2.6 & 2.7
The applied view
Watch the video measures of center.
- What variable is examined in comparing men and women workers at the beginning of the video?
- Would you describe the shape of the distribution of men’s weekly wages as symmetric, skewed to the left or skewed to the right?
- What is the most important difference between the distributions of weekly wages for men and for women?
- Would a few very large incomes pull the mean of a group of incomes up, down, or leave the mean unaffected?
- 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.
- What variable is used to compare different brands of hot dogs?
- What name do we give to the value for which one-quarter of the data values falls at or below it?
- What numbers make up a five-number summary?
- How do you calculate the interquartile range?
- 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.
- In comparing monthly precipitation for Portland, Oregon, and Montreal, Canada, why was comparing the mean monthly precipitation rates insufficient?
- Why don’t we measure spread about the mean by simply averaging x − xbar , the deviations of individual data values from their mean?
- 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?
- Can the standard deviation of a set of observations be s = −1.5 ? Explain.
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?