Chapter 2

Question 1

Central Tendency

Answer 1

Typical or most representative value of a group of scores
Middle of the group of scores
Mean, median, mode

Question 2

Mean

Answer 2

Average of a group of scores
Scores added up and divided by the number of scores
Balancing point
Used with equal-interval variables

Question 3

Mode

Answer 3

Value with the greatest frequency in a distribution
Most common single value in a distribution
Poor projection of a value because not many aspects of the distribution are reflected
Used with normal variables

Question 4

Median

Answer 4

Middle score when all the scores in a distribution are arranged from lowest to highest
Can be used to deemphasize an extreme number
Used

Question 5

Outlier

Answer 5

Score with an extreme value (very high or very low) in relation to the other scores in the distribution

Question 6

Variability

Answer 6

How spread out scores in a distribution are
Variation
Less variability are scores close to mean and vice versa

Question 7

Variance

Answer 7

Measure of how spread out a set of scores are

Average of the squared deviations from the mean

Question 8

Deviation Score

Answer 8

Score - Mean

Question 9

Squared Deviation Score

Answer 9

Square of the difference between a score and the mean

Question 10

Sum of the Squared Deviation

Answer 10

Total of each score’s squared difference from the mean

Question 11

Standard Deviation

Answer 11

Square root of the average of the squared deviations from the mean
Roughly, the SD is the average amount that scores differ from the mean
Square root of the variance

Question 12

Computational Formula

Answer 12

Shortcut to simplify figuring

Question 13

Definitional Formula

Answer 13

Equation for a statistical procedure directly showing the meaning of the procedure