• Read linear regression, predictors and the stock market in preparation for lab
  • (to turn in) A study comparing the number of years of experience of New York City police to the number of tickets they give per week revealed the following data:
    x: No. years experience 3 8 2 15 5 20 1 10 7 12
    y: No. tickets per week 42 30 54 12 32 8 75 28 20 15


    The regression line for this data is y = -2.932x + 55.038.
    1. What does this line predict for police with 25 years experience? Explain why this prediction is not reliable.
    2. The value for the correlation coefficient here is r = -0.86. Calculate r2.
    3. Next explain what this says about the strength of the relationship between years on the job and number of tickets issued by pulling the relevant statistical word from the following r2 table:
      below 10% no
      10% to 25% weak
      25% to 65% moderate
      above 65% strong
    4. Explain the meaning of the slope of the regression line y = -2.932x + 55.038 in the context of the problem, ie using the language of years experiences and tickets.
    5. Explain the meaning of the y-intercept of the regression line in the context of the problem, ie using the language of years experiences and tickets.
    6. EXACTLY what prediction of the years of experience required for 37 tickets does the equation of the regression line give (plug in 37 y-value and solve for x)? Show work!
  • You'll need your stock graph as well as the Excel stock file for lab on Monday.