Ch 5 - Measures of Variability

Question 1

dispersion (variability)

Answer 1

the degree to which individual data points are distributed around the mean

Question 2

range

Answer 2

the distance from the lowest to the highest score

Question 3

interquartile range

Answer 3

the range of the middle 50% of the observations

Question 4

trimmed samples

Answer 4

samples w/ a percentage of the extreme scores removed

Question 5

trimmed statistics

Answer 5

statistics calculated on trimmed samples

Question 6

mean absolute deviation (m.a.d.)

Answer 6

the average of the absolute values of the deviations from the mean

Question 7

sample variance (s2)

Answer 7

sum of the squared deviations about the mean divided by N - 1

Question 8

population variance ( )

Answer 8

variance of a population; usually estimate, rarely computed

Question 9

standard deviation (s or ___)

Answer 9

the square root of the variance

Question 10

bias

Answer 10

a property of a statistic whose long-range average is not equal to the parameter it estimates

Question 11

expected value E( )

Answer 11

the long-range average of a statistic over repeated samples

Question 12

boxplot

Answer 12

a graphical representation of the dispersion of a sample

Question 13

box-and-whisker plot

Answer 13

a graphical representation of the dispersion of a sample

Question 14

hinges (quartiles)

Answer 14

those points that cut off the bottom and top quarter of a distribution

Question 15

quartile location

Answer 15

the location of the quartile in an ordered series

Question 16

H-spread

Answer 16

the range btwn the two hinges (also the interquartile range)

Question 17

whisker

Answer 17

line from top and bottom of the box to the farthest point that is no more than 1.5 times the H-spread from the box

Question 18

Winsorized sample

Answer 18

a sample in which trimmed observations are replaced w/ the highest (and lowest) remaining values

Question 19

Winsorized mean

Answer 19

the mean of a Winsorized sample

Question 20

Winsorized variance

Answer 20

the variance of a Winsorized sample

Question 21

Winsorized standard deviation

Answer 21

the standard deviation of a Winsorized sample

Question 22

σ2

Answer 22

/