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Percentage Quizzes & Trivia

Questions and Answers
  • 1. 
    Assuming that batting averages have a bell-shaped distribution, arrange these in ascending order: I.  An average with a z-score of -1. II.  An average with a percentile rank of 20%. III.  An average at the first quartile.
    • A. 

      I, II, III

    • B. 

      III, I, II

    • C. 

      II, I, III

    • D. 

      II, III, I

    • E. 

      III, II, I

  • 2. 
    Which of the following are true statements? I.  The area under the standard normal curve between 0 and 2 is twice the area between 0 and 1. II.  The area under the standard normal curve between 0 and 2 is half the area between -2 and 2. III.  For the standard normal curve, the interquartile range is approximately 3.
    • A. 

      I and II

    • B. 

      I and III

    • C. 

      II and III

    • D. 

      I, II and III

    • E. 

      None of the above gives the complete set of true responses.

  • 3. 
    Populations P1 and P2 are normally distributed and have identical means.  However, the standard deviation of P1 is twice the standard deviation of P2.  What can be said about the percentage of observations falling within two standard deviations of the mean for each population?
    • A. 

      The percentage for P1 is twice the percentage for P2.

    • B. 

      The percentage for P1 is greater, but not twice as great, as the percentage for P2.

    • C. 

      The percentage for P2 is twice the percentage for P1.

    • D. 

      The percentage for P2 is greater, but not twice as great, as the percentage for P1.

    • E. 

      The percentages are identical.

  • 4. 
    A trucking firm determines that its fleet of trucks averages a mean of 12.4 miles per gallon with a standard deviation of 1.2 miles per gallon on cross-country hauls.  What is the probability that one of the trucks averages fewer than 10 miles per gallon?
    • A. 

      .0082

    • B. 

      .0228

    • C. 

      .4772

    • D. 

      .5228

    • E. 

      .9772

  • 5. 
    The average noise level in a restaurant is 30 decibels with a standard deviation of 4 decibels.  Ninety-nine percent of the time it is below what value?
    • A. 

      20.7

    • B. 

      32.0

    • C. 

      33.4

    • D. 

      37.8

    • E. 

      39.3

  • 6. 
    Cucumbers grown on a certain farm have weights with a standard deviation of 2 ounces.  What is the mean weight if 85% of the cucumbers weigh less than 16 ounces?
    • A. 

      13.92

    • B. 

      14.30

    • C. 

      14.40

    • D. 

      14.88

    • E. 

      15.70

  • 7. 
    The mean score on a college placement exam is 500 with a standard deviation of 100.  Ninety-five percent of the test takers score above what?
    • A. 

      260

    • B. 

      336

    • C. 

      405

    • D. 

      414

    • E. 

      664

  • 8. 
    The average life expectancy of males in a particular town is 75 years, with a standard deviation of 5 years.  Assuming that the distribution is mound-shaped and symmetric, the approximate 15th percentile in the age distribution is
    • A. 

      60

    • B. 

      65

    • C. 

      70

    • D. 

      75

    • E. 

      80

  • 9. 
    A random survey was conducted to determine the cost of residential gas heat.  Analysis of the survey results indicated that the mean monthly cost of gas was $125, with a standard deviation of $10.  What is the z-score of a house with a gas bill of $150 per month?
    • A. 

      -2.5

    • B. 

      0.40

    • C. 

      1.5

    • D. 

      2.5

    • E. 

      25

  • 10. 
    A symmetric, mound-shaped distribution has a mean of 42 and a standard deviation of 7.  Which of the following is true?
    • A. 

      There are more data values between 42 and 49 than between 28 and 35.

    • B. 

      The maximum value is less than 70.

    • C. 

      Approximately 95% of the data lie between 35 and 49.

    • D. 

      The interquartile range is approximately 14.

    • E. 

      None of these is true.

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