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PACIFICA

GRADUATE INSTITUTE

Please turn in all worksheets showing how you got your answers.

 

Data Set A:

18

15

14

21

16

15

16

17

15

17

16

17

15

17

13

15

22

20

14

16

14

21

14

15

15

 

 

  1. Draw a box and whiskers plot for Data Set A.
     
  2. What is the 60th percentile for the data in Data Set A?
     
  3. What is the mode for the data in Data Set A?
     
  4. Are the data in Data Set A skewed? If so, are they positively or negatively skewed? Answers to #1 - 4.
     
  5. If Data Set A is an entire population, what is its mean (μ)?
     
  6. If Data Set A is an entire population, what is its variance (σ2)?
     
  7. If Data Set A is a randomly selected sample from a larger population, what is the mean ()?
     
  8. If Data Set A is a randomly selected sample from a larger population, what is its variance (s2)? Answers to #5 - 8.
     
  9. Using a full hypothesis testing procedure, test the data in Data Set A to see if this randomly selected sample was drawn from a population that has a mean of 16. Use an alpha level of .05. Answer
     
  10. A group of 219 randomly selected patients were tested to determine Idation levels. Idation levels are normally distributed with a mean of 23 and a variance of 25. How may patients would we expect to score between 21 and 28? Answer
     
  11. You have developed the Bozo Lie Detector Exam. This Exam tells us whether a person is lying or truthful. To test your exam, you hire a number of people to take your exam. Some of the people are told to be honest and others are told to be dishonest during the exam. Here are the results:
  12. Truth

    Honest

    Dishonest

    Test
    Result

    Truthful

    319

    4

    Lying

    12

    9

    What are the sensitivity, specificity, positive predictive value, and negative predictive values? Answer

     

    Data Set B:

    x

    y

     

    x

    y

     

    x

    y

    79

    15

     

    85

    24

     

    73

    15

    96

    25

     

    72

    17

     

    68

    19

    76

    11

     

    90

    18

     

    80

    19

    66

    23

     

     

     

     

     

     

     

  13. What is the correlation coefficient (r) for the data in Data Set B? Does this differ significantly from ρ = 0 at alpha = .05 (two-tailed)? Do a complete hypothesis test. Answer
     
  14. What is the equation for the regression line in Data Set B? Answer
     
  15. Draw a scatter plot showing the data and regression line in Data Set B? Answer
     
  16. A depression test has a known mean of 215 and known standard deviation of 39. If you were to treat 25 patients at an α = .05 level, one-tailed, what would their mean depression score need to be reduced to before you would believe your therapy worked? If your therapy truly reduced depression scores by 10 points, how powerful would this test be? Answer If you increase the number of patients to 100, how powerful would this test be? Answer
     

Extra Credit - pertains to Chapter 14

You sell two types of chocolate, dark and light. You know that nationally more people buy light chocolate than dark, but you are wondering if this preference is stronger in one part of the county than another. You gather information on how many tons of chocolate were sold in the western, middle, and eastern parts of the country from the CCCCC (Cross Country Commission on Chocolate Consumption). Conduct a full hypothesis test using a χ2 test at the α = .05 level.
 

Part of Country

West

Middle

East

Dark

65

72

61

Light

91

155

145

Answer

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