Psych 218 Midterm #1

Front 1

parameter

Back 1

a numerical quality such as the average that summarizes some characteristic of the population

Front 2

statistic

Back 2

a numerical quanitty such as the average that summarizes some characteritstic of the sample

Front 3

random assignment

Back 3

random assignment to different groups assures that the two groups are approximetely equal

Front 4

random selection

Back 4

that each person in the population has an equal chance of being in the sample
-this is done by listing everyone in the pop than using s method such as picking out of a hat to get people for sample

Front 5

nominal

Back 5

each obervation placed into a single category and the categories are not ordered
ex: gender religion

Front 6

ordinal

Back 6

ibservations are ranked but the differences are not meaningful
ex: movie ratings

Front 7

interval

Back 7

observations are equally spaced but zero has not true meaning
ex: temperature

Front 8

ratio

Back 8

observations are equally spaced but there is a true meaning for 0
ex: weight. length

Front 9

Finding the range

Back 9

the highest score- the lowest score

Front 10

number of possible scores

Back 10

the highest score-the lowest score+ 1

Front 11

frequency histograms

Back 11

the x axis gives the score values for grouped or ungrouped data, midpoint is plotted for each class interval or the upper and lowe limits of the interval
the y axis gives the frequency for each value

Front 12

symetric distributions

Back 12

mean should equal median and it dodenst matter which one you use

Front 13

positively skewed

Back 13

tail in positive direction
-mean will be larger than median
-and mean will be misleading as measure of central tendency

Front 14

negatively skewed

Back 14

tail in negative direction
-mean is smaller than median

Front 15

semi interquartile range

Back 15

is half the interquartile range
-used as a measure to accompany median
-and is appropriate for ordinal data
Q3-Q1/2

Front 16

rule #1 for changing mean and variability

Back 16

if a constant is added or subtracted from every score the mean of the transformed score is changed by the value of the constant

Front 17

rule # 2 for changing mean and variability

Back 17

if a constant is added to or subtracted to every score the standard deviation and variance of the transformed scores both remain the same

Front 18

rule # 3 for changing mean and variability

Back 18

if every score in the distribution is multiplied by a constant the mean of the transformed scores becomes the product of the old mean and the constant

Front 19

rule #4 for changing mean and variability

Back 19

if every score in the distribution is multiplied by a postive constant the standard deviation of the trasnformed scores is the product of the original variance and the square root of the constant