Chapter 1

Question 1

Bimodal distribution

Answer 1

Frequency distribution with two approximately equal frequencies, each clearly larger than any of the others.

Question 2

multimodal distribution

Answer 2

frequency distribution with two or more high frequencies separated by a lower frequency; a bimodal distribution is the special case of two high frequencies.

Question 3

rectangular distribution

Answer 3

frequency distribution in which all values have approximately the same frequency.

Question 4

Symmetrical distribution

Answer 4

Distribution in which the pattern of frequencies on the left and right side are mirror images of each other.

Question 5

Skewed distribution

Answer 5

distribution in which the scores pile up on one side of the middle and are spread out on the other side; distribution that is not symmetrical.

Question 6

Floor effect

Answer 6

Situation in which many scores pile up at the low end of a distribution (creating skewness to the right) because it is not possible to have any lower score.

Question 7

Ceiling effect

Answer 7

Situation n which many scores pile up at the high end of distribution (creating skewness to the left) because it is not possible to have a higher score.

Question 8

Normal curve

Answer 8

specific, mathematically defined, bell-shaped frequency distribution that is symmetrical and unimodal; distributions observed in nature and in research commonly approximate it.

Question 9

Kurtosis

Answer 9

Extent to which a frequency distribution deviates from a normal curve in terms of whether its curve in the middle is more peaked or flat than the normal curve.