Chapter 4 Quiz Review

What does SS stand for?

• Sum of Squared Deviations

• Summation of Product Scores

• Sum of Standardized Scores

• Sum of Scores

Answer explanation

SS stands for the "Sum of Squared Deviations" or just the "Sum of Squares."

____ measures the standard distance from the mean, and ____ measures the average squared distance from the mean.

• Standard deviation; Variance

• Sum of Squares; Deviation Scores

• Variance; Standard Deviation

• Deviation Scores; Sum of Squares

Answer explanation

Standard deviation measures the standard distance from the mean, and variance measures the average squared distance from the mean.

What is the standard deviation for the following set of n = 5 scores; 10, 10, 10, 10, 10?

• 1

• 5

• 10

• 0

Answer explanation

Since there is no variability between the scores, the standard deviation must be zero.

A set of six scores has SS = 30. If the six scores are a sample (n = 6), what is the variance?

• 5

• 6

• 1

• 4

A population has a mean of μ = 70 and a standard deviation of σ = 5. If 10 points were added to every score in the population, what would be the new values for the population mean and standard deviation?

• μ = 80, σ = 15

• μ = 70, σ = 15

• μ = 80, σ = 5

• μ = 70, σ = 5

Answer explanation

The new mean would be μ = 80 since 10 was added to every score. However, the distance between scores would still be σ = 5. Adding a constant to every score does NOT affect the standard deviation.

For a distribution of scores with μ = 50 and X = 53, what is your deviation score?

• 0

• -3

• 1

• 3

Answer explanation

A deviation is a score's distance from the mean and uses the formula: X - μ. Using this formula, we should calculate 53 - 50 = 3.

What is the expected value of adding deviation scores up?

• 0

• SS

• SD

• 1

Answer explanation

The total of the distances above the mean is exactly equal to the total of the distances below the mean. Thus, the complete set of deviations always adds up to zero. If you did not get zero, make sure to check your answers!

__ is the symbol used to denote a population's standard deviation; __ is the symbol used to denote a sample's standard deviation.

• N; n

• σ; n

• N; S

• σ; S

Answer explanation

"σ" is the symbol used to denote a population's standard deviation; "S" is the symbol used to denote a sample's standard deviation.

What is the last step in solving for standard deviation, according to Dr. Story?

• "Unsquaring" your SS

• "Unsquaring" the variance

• "Unsquaring" the deviation scores

• "Unsquaring" your degrees of freedom

A population statistic is biased if the average value of the statistic either overestimates or underestimates the corresponding sample size.

• True

• False

Answer explanation

This is false! A sample statistic is biased if the average value of the statistic either underestimates or overestimates the population parameter. That is why we must use n - 1 when solving for standard deviation to make the statistic unbiased.