Chapter 3

Question 1

Measurement

Answer 1

The act of assigning number or symbols to characteristics of things according to rules

Question 2

Scale

Answer 2

A set of numbers or symbols whose properties model empirical properties of the objects to which the numbers are assigned

Question 3

Discrete scale

Answer 3

Sample space can be counted, numbers between sample space members are not allowed

Question 4

Sample space

Answer 4

The values a variable can take on (ie freshman, sophomore, jr, sr)

Question 5

Continuous scale

Answer 5

Values can be any real number in the scale’s sample space, can have fractions or decimals

Question 6

Error

Answer 6

The collective influence of all of the factors on a test score or measurement beyond those specifically measured by the test or measurement

Question 7

Nominal scales

Answer 7

Involve classification or categorization based on one or more distinguishing characteristics, where all things measured must be placed into mutually exclusive and exhaustive categories, no inherent/defined order

Question 8

Ordinal scales

Answer 8

Assign people to categories that have a clear and uncontroversial order (Never, Sometimes, Often), don’t imply how much greater one ranking is than another, no absolute zero point

Question 9

Interval scales

Answer 9

Meaningful distances between numbers, no absolute zero point, can’t say IQ of 100 is twice as much intelligence as 50

Question 10

Ratio scales

Answer 10

All properties of other scales and a true zero point

Question 11

Distribution

Answer 11

A set of test scores arrayed for recording or study

Question 12

Raw score

Answer 12

Straightforward, unmodified accounting of performance that is usually numerical

Question 13

Frequency distribution

Answer 13

All scores are listed alongside the number of times each score occurred

Question 14

Grouped frequency distribution

Answer 14

Test score intervals replace the actual test score

Question 15

Histogram

Answer 15

A graph with vertical lines drawn at the true limits of each test score, forming a series of continuous rectangles

Question 16

Bar graph

Answer 16

Numbers indicative of frequency appear on Y-axis, reference to categorization on x-axis, bars aren’t contiguous

Question 17

Frequency polygon

Answer 17

Continuous line connecting points where test scores or class intervals meet frequencies

Question 18

Measure of central tendency

Answer 18

A statistic that indicates the average or midmost score between the extreme scores in a distribution- mean, median

Question 19

Variability

Answer 19

An indication of how scores in a distribution are scattered or dispersed

Question 20

Measures of variability

Answer 20

Statistics that describe the amount of variation in a distribution, ie range, interquartile range, semi-interquartile range, average deviation, standard deviation, variance

Question 21

Interquartile range

Answer 21

Q3 - Q1

Question 22

Semi-interquartile range

Answer 22

Interquartile range divided by 2

Question 23

Average deviation

Answer 23

Calculate each deviation from mean, ignore signs, average out (rarely used bc ignores signs)

Question 24

Standard deviation

Answer 24

A measure of variability equal to the square root of the average squared deviations about the mean

Question 25

Variance

Answer 25

Equal to the mean of the squares of the differences between the scores in the distribution and the mean, square and sum all deviation scores and divide by number of scores

Question 26

Skewness

Answer 26

The nature or extent to which symmetry is absent in a distribution

Question 27

Kurtosis

Answer 27

The steepness of a distribution in its center

Question 28

Platykurtic

Answer 28

Relatively flat

Question 29

Leptokurtic

Answer 29

Relatively peaked

Question 30

Mesokurtic

Answer 30

Neither flat nor peaked

Question 31

Normal curve

Answer 31

Bell-shaped, smooth curve that is highest at center, tapers on both sides, perfectly symmetrical, no skewness, mean median and mode are equal

Question 32

Tail

Answer 32

Area on normal curve between 2 and 3 SDs above/below mean

Question 33

Standard score

Answer 33

A raw scores that has been converted from one scale to another scale that has some arbitrarily set mean and SD

Question 34

Z score

Answer 34

Result of converting raw score into number indicating how many SDs the raw score is above or below the mean

Question 35

T score

Answer 35

Score on scale with mean at 50 and SD of 10,

Question 36

Stanine

Answer 36

Standard score on scale with mean of 5, SD of approx 2

Question 37

Normalizing a distribution

Answer 37

Stretching a skewed curve into the shape of a normal curve and creating a corresponding scale of standard scores

Question 38

Coefficient of correlation

Answer 38

A number that provides us with an index of the strength of the relationship between two things

Question 39

Correlation

Answer 39

Expression of the degree and direction of correspondence between two things

Question 40

Coefficient of determination

Answer 40

Indication of how much variance is shared by two variables

Question 41

Spearman’s rho

Answer 41

Coefficient of correlation used when sample size is small and both sets of measurements are in ordinal/rank-order form

Question 42

Bivariate distribution

Answer 42

Scatterplot

Question 43

Outlier

Answer 43

Extremely atypical point located at a relatively long distance from the rest of the coordinate points

Question 44

Meta-analysis

Answer 44

A family of techniques used to statistically combine information across studies to produce single estimates of the data