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**Chapter 3 - Multiple Choice**

Choose the best answer for each question.

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**Question 1**

**1 pts**

A sample of *n* = 6 scores has a mean of M = 5. One person with a score of X = 12 is added to the distribution. What is the mean for the new set of scores?

M = 5

M = 6

M = 7

M = 8

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**Question 2**

**1 pts**

A researcher is measuring the amount of time needed to solve a set of anagrams for a sample of *n* = 15 students. However, one of the participants fails to solve the problems so the researcher has an undetermined score. What is the best measure of central tendency for these data?

The mean

Central tendency cannot be determined for the these data

The mode

The median

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**Question 3**

**1 pts**

What is the median for the population of scores shown in the frequency distribution table?

**Xf**5142332412

2.5

4

3.5

3

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**Question 4**

**1 pts**

For a positively skewed distribution with a mean of M = 20, what is the most probable value for the median?

Greater than 20

Less than 20

Cannot be determined from the information given

Exactly 20

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**Question 5**

**1 pts**

What is the mode for the population of scores shown in the frequency distribution table?

**Xf**5142332412

3

3.5

4

2

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**Question 6**

**1 pts**

One sample has *n* = 4 scores and M = 10. A second sample has *n* = 8 scores and M = 4. If the two samples are combined, what is the mean for the combined sample?

14/12 = 1.167

14/5 = 2.8

Cannot be determined from the information given

71/12 = 6

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**Question 7**

**1 pts**

After 5 points are subtracted from every score, the sample mean is found to be M = 24. What was the mean for the original sample?

Cannot determine without knowing the number of scores in the sample

19

24

29

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**Question 8**

**1 pts**

A set of N = 8 scores has a mean of *µ* = 11. If 16 points are added to one of the scores, what is the new value for the population mean?

11

10

12

13

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**Question 9**

**1 pts**

My electric bills for June, July, and August last summer were $75, $75, and $150, respectively. What was the mean amount for the three bills?

$150

$125

$75

$100

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**Question 10**

**1 pts**

A distribution is positively skewed. Which is the most probable order, from smallest to largest, for the three measures of central tendency?

Median, mean, mode

Mean, mode, median

Mode, median, mean

Mean, median, mode

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**Chapter 4 - Multiple Choice**

Choose the best answer for each question.

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**Question 11**

**1 pts**

A population of N = 5 scores has ΣX = 10 and ΣX2 = 45. What is the value of SS for this population?

25

45

4

9

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**Question 12**

**1 pts**

A sample of *n* = 6 scores has ΣX = 15 and ΣX2 = 60. For this sample, what is the value of SS?

45

60

25

22.5

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**Question 13**

**1 pts**

Which of the following actions will have no effect on the value of the standard deviation?

Subtract 5 points from every score in the distribution

All of the other actions will change the value of the standard deviation

Multiply each score in the distribution by 2

Divide each score in the distribution by 2

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**Question 14**

**1 pts**

What is the variance for the following population of scores?

Scores: 1, 3, 2, 4, 5

6

1.5

1.22

2

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**Question 15**

**1 pts**

For the following scores, which of the following actions will decrease the range?

Scores: 3, 7, 10, 15

Subtract 3 points from the score X = 7

Subtract 3 points from the score X = 15

Subtract 3 points from the score X = 10

Subtract 3 points from the score X = 3

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**Question 16**

**1 pts**

On an exam with a mean of *μ* = 70, you have a score of X = 65. Which of the following values for the standard deviation would give you the highest position within the class?

σ = 1

σ = 5

Cannot determine from the information given

σ = 10

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**Question 17**

**1 pts**

What is the value of SS (sum of squared deviations) for the following population?

Population: 2, 3, 4, 5, 1

55

11

15/5 = 3

11/5 = 2.20

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**Question 18**

**1 pts**

The sum of the squared deviation scores is SS = 30 for a sample of *n* = 6 scores. What is the variance for this sample?

5

6

180

150

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**Question 19**

**1 pts**

If sample variance is computed by dividing SS by *n*, then the average value of the sample variances from all the possible random samples will be _______ the population variance.

smaller than

unrelated to

exactly equal to

larger than

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**Question 20**

**1 pts**

One sample is selected to represent scores in treatment 1 and a second sample is used to represent scores in treatment 2. Which set of sample statistics would present the clearest picture of a real difference between the two treatments?

M1 = 38, M2 = 40, and both variances = 43

M1 = 36, M2 = 40, and both variances = 43

M1 = 38, M2 = 40, and both variances = 6

M1 = 36, M2 = 40, and both variances = 6