STAT 110 Practice Exam 3

  1. T F If the data are extremely left skewed, the median will be larger than the mean.
  2. T F A negative value for skewness would indicate the data are right skewed.
  3. T F The median of a data set is affected by outliers.
  4. A study in Sweden looked at former elite soccer players, people who had played soccer but not at an elite level, and people of the same age who did not play soccer at all. The contingency table below gives the number of individuals in each group who had arthritis of the hip or knee by their mid-50s.

Elite / Non-elite / Did not play / Total
Arthritis / 10 / 9 / 24 / 43
No Arthritis / 61 / 206 / 548 / 815
Total / 71 / 215 / 572 / 858

Research Question – Is there a relationship between having arthritis of the hip or knee
and a person’s soccer status?

  1. Determine the appropriate null and alternative hypotheses that would be used to test the research question of interest.
  1. Using the JMP output given below, carry out the remainder of the hypothesis test. Make sure to clearly check the conditions of the test, state your test statistic, p-value and conclusion in context.
  1. The ages of CEOs was recorded for 61 top-ranked small companies in America in 1993. Use the following JMP output to answer the questions below.

  1. What is the average (mean) age of the CEO’s? Be sure to use the appropriate statistical notation in your answer.
  1. How would you describe the shape or distribution of the CEO ages?
  1. Looking at the boxplot, are there any potential outliers in the CEO ages data set? Explain.
  1. Give the standard deviation and variance for the CEO ages. Make sure to use appropriate statistical notation.
  1. Between what two values does the middle 95% of the data lie?

Matching

Match each of the following studies to their appropriate hypotheses.

  1. A B C D E F It has been hypothesized that the mean pulse rate for college
    students is about 72 beats per minute. A random sample of 57
    students at WSU was taken and their pulse rates recorded. You
    are interested in testing whether the average pulse rate is 72
    beats per minute or not.
  2. A B C D E F A study was conducted off the coast of Florida investigating
    lengths of great white sharks. It has been stated that the average
    great white shark is 15 feet long. However, after years of shark
    fishing expeditions, fishermen are convinced that the average
    length is actually less than 15 feet. The researchers conducted a
    study to test the fishermen’s claim.
  3. A B C D E F Many cars have a recommended tire pressure of 32 psi (pounds
    per square inch). At a roadside vehicle safety checkpoint
    officials checked the tire pressure of 50 randomly selected cars.
    They were interested in knowing if drivers on average have too
    little air pressure in their tires.

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