Research Methods -- CRJU 3601 – Homework Answers

Ethics in Research (Percentage Between)

Problem 1 The mean 75 with a standard deviation of 23. Determine percentages that fall between these pairs of scores:

52 and 98, 29 and 121, 56 and 71, 100 and 122, 35 and 125

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Problem 1 Answers

Raw 52.00 Raw 98.00

Z -1.00 Z 1.00

Percent between = 68.26%

Raw 29.00 Raw 121.00

Z -2.00 Z 2.00

Percent between = 95.44%

Raw 56.00 Raw 71.00

Z -0.83 Z -0.17

Percent between = 22.92%

Raw 100.00 Raw 122.00

Z 1.09 Z 2.04

Percent between = 11.72%

Raw 35.00 Raw 125.00

Z -1.74 Z 2.17

Percent between = 94.41%

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Problem 2 The mean of 42 and a standard deviation of 18.

a. What is the percentage of scores that fall between 77.28 and 6.72

b. What is the percentage between 43 and 50

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Problem 2 Answers

a. The percentage of scores that fall between 77.28 and 6.72 is 95%

b. The percentage between 43 and 50 is 14.61%

(or .15.01% when Z-Score of .055 is not rounded to .06)

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Problem 3 Mean is 200, standard deviation is 35. What is percentage between 145 and 180

Problem 3 Answer The percentage between 145 and 180 is 22.61%

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Problem 4 The mean is 8,000, standard deviation of 2500:

a. What is the percentage between 5750 and 9750

b. What is the percentage between 8000 and 10500

Problem 4 Answer a. About 58% b. 34.13%

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Problem 5 The mean is 200 with a standard deviation of 25. What is the percentage between 183 and 240?

Problem 5 Answer The percentage between 183 and 240 is 69.70%

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Problem 6 a. What is the percentage between 491 and 518 when = 500 and s = 100?

b. What percentage of scores fall between 72 and the mean when = 50 and s = 10?

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Problem 6 Answer a. 10.73% b. 48.61%