Psych Chap 4

Front 1

variability

Back 1

a measure of the degree to which the scores in a distribution are clustered together or spread apart

Front 2

range

Back 2

the distance from the upper real limit of the highest score to the lowest real limit of the lowest score

Front 3

first quartile

Back 3

the score that separates the lowest 25% of a distribution from the highest 75%

Front 4

third quartile

Back 4

the score that separates the lowest 75% of a distribution from the highest 25%

Front 5

interquartile range

Back 5

the distance from the first quartile to the third quartile

Front 6

deviation score

Back 6

the distance and direction from the mean to a specific score

Front 7

population variance

Back 7

the average squared distance from the mean; the mean of the squared deviation

Front 8

population standard deviation

Back 8

the square root of the population variance; a measure of the standard distance from the mean

Front 9

sample variance

Back 9

the sum of the squared deviations divided by df = n-1. An unbiased estimate of the population variance.

Front 10

sample standard deviation

Back 10

the square root of the sample variance

Front 11

degrees of freedom

Back 11

the number of scores in a sample that are independent and free to vary with no restriction. df=n-1

Front 12

biased statistic

Back 12

a statistic that, on average, consistently tends to overestimate (or underestimate) the corresponding population parameter

Front 13

unbiased statistic

Back 13

a statistic that, on average, provides an accurate estimate of the corresponding population parameter. the sample mean and sample variance are unbiased statistics.