Hw. 2 Ch. 3 & 4

B. 5

A researcher reports that his sample of n =100 students has a mean self-esteem score of M = 60 and variance of s2 = 25. What is the standard deviation of self-esteem scores in this sample?

C. The sample mean would become larger than M=5.

A sample of n = 10 scores has a mean of M = 5. How would the sample mean changed if one score of X = 9 was added to the sample?

B. M = 10

A sample of n = 20 scores has a mean of M = 10. One person with a score of X = 10 is added to the distribution. What is the mean for the new set of scores?

C. s2 = 8; σ2 = 7.2

A set of 10 scores has SS = 72. If the scores are a sample, the sample variance is ____, and if the scores are a population, the population variance is ____.

C. Equal 15

For a perfectly symmetrical distribution with a median of 15, what is the value of the mean?

D. the differences between scores are relatively large and they tend to be relatively far away from the mean.

If a dataset has a large standard deviation that means_____

C. Negatively skewed

If a sample of test scores has a mean of M = 45, a median of 55, and a mode of 65. What is the most likely shape of this population distribution?

D. σ = 2

On a quiz with a mean of M = 25, you have a score of X = 29. Which of the following values of standard deviation would give you the highest position within the class?

B. in an extremely skewed frequency distribution.

Under what circumstances is the median likely to produce a better measure of central tendency than the mean?

n = 6 M = (3 + 4 + 2 + 2 + 5 + 2)/6 = 18/6 = 3 SS = (3-3)2 + (4-3)2 + (2-3)2 + (2-3)2 + (5-3)2 + (2-3)2 = 0 + 1+ 1+ 1 + 4 + 1 = 8 s2 = SS/n-1= 8/5 = 1.6 s = SqRoot of 1.6 = 1.26

Using the definitional formula compute the sum of squared deviations (SS), the sample variance and the sample standard deviation for the following sample.. Show your work (i.e., write all computational steps). Sample scores (X): 3, 4, 2, 2, 5, 2

D. 35/10 = 3.50

What is the mean for the population of scores shown in the frequency distribution table? X f 6 1 5 3 3 4 2 0 1 2

C. 12

What is the median for the population of scores shown in the frequency distribution table? X f 15 1 14 3 13 4 12 1 11 2 10 4 9 2

C. 4

What is the mode for the population of scores shown in the frequency distribution table? X f 10 2 6 9 5 4 3 2 2 5 1 3

D. 26

What is the value of SS (Sum of Squared Deviation) for the following population? Population scores (X): 5, 8, 7, 12

B. 15

What is the value of the median for the following set of scores? Scores (X): 3, 6, 8, 13, 15, 19, 22, 25, 28

C. 55% of the scores are above the median.

Which of the following statements cannot be true for a frequency distribution of scores? A. 55% of the scores are above the mean B. 55% of the scores are above the mode. C. 55% of the scores are above the median. D. All of the other options are false statements.

B. σ

Which of the following symbols identifies the population standard deviation?

D. σ2

Which of the following symbols identifies the population variance?

A. s

Which of the following symbols identifies the sample standard deviation?

C. s2

Which of the following symbols identifies the sample variance?