Central Tendency and Variability

Question 1

central tendency

Answer 1

statistical measure descriptive of summary of all scores in a distribution.

Question 2

mean

Answer 2

average for all scores
- best for symmetrical distributions

Question 3

median

Answer 3

score that falls in the middle
- best used for skewed distributions with one or more outliers

Question 4

mode

Answer 4

most commonly occurring score
- best used for nominal data, a multimodal distribution, or if a particular score dominates a distribution

Question 5

if value of score is increased, mean…

Answer 5

will also increase

Question 6

if value of score is decreased, mean…

Answer 6

will also decrease

Question 7

if you add a score above the mean, mean…

Answer 7

will increase

Question 8

if you add a score below the mean, mean…

Answer 8

will decrease

Question 9

outliers

Answer 9

extreme scores can significantly impact the mean, rendering the mean of little use in describing the distribution

Question 10

how much of the data falls within 1 standard deviation?

Answer 10

68%

Question 11

how much of the data falls within 2 standard deviations?

Answer 11

95%

Question 12

how much of the data falls within 3 standard deviations?

Answer 12

99%

Question 13

variability

Answer 13

statistical measure descriptive of the amount of spread among scores in a distribution

Question 14

range

Answer 14

the difference between the highest score obtained and the lowest score obtained

Question 15

deviation

Answer 15

amount a given score differs from the mean of all scores

Question 16

standard deviation

Answer 16

typical amount by which scores fall from the mean

Question 17

variance

Answer 17

average of the squared deviations from the mean

Question 18

inferential statistics

Answer 18

used to test hypotheses and differences

Question 19

null hypothesis

Answer 19

two groups will not differ significantly from one another