Chapter Statistics

10 Questions | Total Attempts: 272

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Chapter Statistics

Questions and Answers
  • 1. 
    A simple random sample of 35 world-ranked chess players provides the following statistics: Number of hours of study per day:  ,  Yearly winnings:  ,  Correlation:   Based on this information, what is the resulting linear regression equation?
    • A. 

      Winnings = 4850 Hours + 178,000

    • B. 

      Winnings = 6300 Hours + 169,000

    • C. 

      Winnings = 31,200 Hours + 14,550

    • D. 

      Winnings = 32,300 Hours + 7750

    • E. 

      Winnings = 42,000 Hours - 52,400

  • 2. 
    A scatterplot of a company's revenues versus time indicates a possible exponential relationship.   A linear regression on  against  gives  with .  Which of the following are valid conclusions? I.  One the average, revenue goes up 0.82 thousand dollars (or $820) per year. II.  The predicted revenue in year 2005 is approximately 59 million dollars. III.  53% of the variation in revenue can be explained by variation in time.
    • A. 

      I

    • B. 

      II

    • C. 

      III

    • D. 

      I and III

    • E. 

      None of the above are valid conclusions.

  • 3. 
    Suppose the regression line for a set of data, , passes through the point .  If  and  are the sample means of the x and y values, respectively, then 
    • A. 
    • B. 
    • C. 
    • D. 
    • E. 
  • 4. 
    Consider the following residual plot: Which of the following scatterplots could have resulted in the above residual plot?  (The y-axis scales are the same in the scatterplots as in the residual plot.)
    • A. 
    • B. 
    • C. 
    • D. 
    • E. 

      None of these could result in the given residual plot.

  • 5. 
    Which of the following is a correct conclusion based on the residual plot displayed?
    • A. 

      The line overestimates the data.

    • B. 

      The line underestimates the data.

    • C. 

      It is not appropriate to fit a line to these data since there is clearly no correlation between the variables.

    • D. 

      The data are not related.

    • E. 

      None of these

  • 6. 
    A simple random sample of years and earnings was organized into pairs (time in years, earnings in $1,000s).  The scatterplot appears exponential and the transformation  is applied to the data.  Linear regression is done on the transformed data and the following results are given: Which of the following is a valid conclusion?
    • A. 

      The earnings gained after 12 years are approximately 5.8759.

    • B. 

      The earnings gained after 12 years are approximately 356,345.

    • C. 

      The earnings will increase by 0.464 thousand dollars each year.

    • D. 

      The original investment was $307.90

    • E. 

      None of these is valid.

  • 7. 
    The heart disease death rates per 100,000 people in the United States for certain years, as reported by the National Center for Health Statistics, were Year 1950 1960 1970 1975 1980 Death rate 307.6 286,2 253.6 217.8 202.0 Which of the following is a correct interpretation of the slope of the best-fitting straight line for the above data?
    • A. 

      The heart disease rate per 100,000 people has been dropping about 3.627 per year.

    • B. 

      The baseline heart disease rate is 7386.87.

    • C. 

      The regression line explains 96.28% of the variation in heart disease death rates over the years.

    • D. 

      The regression line explains 98.12% of the variation in heart disease death rates over the years.

    • E. 

      The heart disease death rate will be zero in the year 2036.

  • 8. 
    Which of the following is the quantity that is minimized by the least squares regression process?
    • A. 
    • B. 
    • C. 
    • D. 
    • E. 
  • 9. 
    Which of the following is a true statement?
    • A. 

      The higher the correlation coefficient, the steeper the line of best fit.

    • B. 

      The correlation coefficient has the same sign as the y-intercept of the least squares regression line.

    • C. 

      A low correlation coefficient indicates a weak relationship between the two variables.

    • D. 

      Two sets of bivariate data can have approximately equal correlation coefficients but very different scatterplots.

    • E. 

      All of these are true.

  • 10. 
    If the correlation coefficient of a bivariate set of data  is , then which of the following is true?
    • A. 

      The variables   and   are linearly related.

    • B. 

      The correlation coefficient of the set   is also  .

    • C. 

      The correlation coefficient of the set   is  .

    • D. 

      The correlation coefficient of the set   is 

    • E. 

      None of these.

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