variability

Question 1

variability

Answer 1

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

Question 2

range

Answer 2

the difference between the the upper real limit for the maximum score and the lower real limit for the minimum score

Question 3

interquartile range

Answer 3

the distance between the first quartile and the third quartile

Question 4

semi-interquartile range

Answer 4

one-half of the distance between the first quartile and the third quartile

Question 5

first quartile

Answer 5

the score (Q1) that separates the lower 25% of the distribution from the rest

Question 6

second quartile

Answer 6

the score (Q2) that separates the distribution exactly in half; equal to the median

Question 7

third quartile

Answer 7

the score (Q3) that separates the lower 75% of the distribution from the rest

Question 8

(population) deviation

Answer 8

distance a given score in a distribution is from the mean (X - μ)

Question 9

mean deviation

Answer 9

0

Question 10

population variance

Answer 10

mean squared deviation (σ^2 = SS/N)

Question 11

(population) standard deviation

Answer 11

square root of the (population) variance (σ = √(SS/N))

Question 12

sum of squares

Answer 12

(SS) sum of the squared deviation scores; SS = Σ (X - μ)^2

Question 13

sum of squares computational formula

Answer 13

SS = (ΣX^2) - (((ΣX)^2) / N)

Question 14

(sample) deviation

Answer 14

distance a given score in a distribution is from the mean (X - X̄)

Question 15

sample variance

Answer 15

mean squared deviation (s^2 = SS/(n - 1))

Question 16

(sample) standard deviation

Answer 16

square root of the (sample) variance (s = √(SS/(n - 1)))

Question 17

degrees of freedom

Answer 17

df = n - 1

Question 18

How many scores in a distribution are free to vary?

Answer 18

The total degrees of freedom for the distribution; df = n - 1

Question 19

sample variance related to degrees of freedom

Answer 19

s^2 = ((sum of squared deviations)/(number of scores free to vary)) = SS/df = SS/(n - 1)

Question 20

What is the standard deviation?

Answer 20

a measure of distance from the mean

Question 21

How do constants affect the standard deviation?

Answer 21

changing each score with a constant changes the standard deviation with the same constant

Question 22

Which measure of variability is least affected by extreme scores?

Answer 22

semi-interquartile range

Question 23

Which measure of variability is most affected by sample size?

Answer 23

range

Question 24

Which measure of variability is least stable under sampling?

Answer 24

range

Question 25

Which measure of variability is best for open-ended distributions?

Answer 25

semi-interquartile range