Stats: Scales of Measurement and Descriptive Statistics

nominal scale

measurement scale that divides variables into unordered categories

nominal

marital status is on a ___ scale

ordinal scale

a scale of measurement in which the measurement categories form a rank order along a continuum

ordinal

NFL rankings are on a ___ scale

qualitative, discrete

nominal and ordinal data are ___ and ___

interval scale

a scale of measurement in which variables are divided rank ordered and intervals between ranks on the scale are all equal in size

interval

IQ is a on a ___ scale

ratio scale

a scale of measurement in which variables are divided rank ordered, intervals between ranks on the scale are all equal in size, and scale has an absolute zero

ratio

age or weight are on a __ scale

quantitative, usually continuous

interval and ratio data are ___ and ___

normal curve

the symmetrical bell-shaped curve that describes the distribution of many physical and psychological attributes. Most scores fall near the average, and fewer and fewer scores lie near the extremes.

low, high

in a positively skewed distribution the majority of scores are __, while in a negatively skewed distribution, the majority of scores are ___

all equal

rank the mean, median, and mode in a normal distribution

mode, median, mean

rank the mean, median, and mode from lowest to highest in a positively skewed distribution

mean, median, mode

rank the mean, median, and mode from lowest to highest in a negatively skewed distribution

median

what is the best measure of central tendency when there are extreme scores or a substantial percentage of maximum scores?

z score

a measure of how many standard deviations the raw score is from the mean, uses the actual population variance

0, 1

z scores have a mean of __ and an SD of __

raw score distribution

the z score distribution is the same as the ___

t score

a measure of how many standard deviations the raw score is from the mean, uses the corresponding sample variance when the population value is not known.

50, 10

T scores have a mean of __ and an SD of __

percentile

Specific point in a distribution of data that has a given percentage of cases below it

flat/a rectangle (because its evenly distributed based on definition of it)

the distribution of percentile scores is __ shaped

50

percentiles have a mean of ___

stanine

a method of scaling test scores on a nine-point standard scale

5, 2

Stanine scores have a with a mean of ___ and a standard deviation of ___

norm referenced, criterion referenced

t, z, percentile are all __-referenced scores, percentage is a ___-referenced score.

60, 84, 34.13%

in a normal distribution, a z score of +1 = T score of ___ = a percentile of ___ = ___% of cases in the normal curve

40, 16, 34.13%

in a normal distribution, a z score of -1 = T score of ___ = a percentile of ___ = ___% of cases in the normal curve

~16%

in a normal distribution, below 1 SD below the mean (and above 1 SD above the mean) accounts for ___% of cases

larger, outer edge

because the majority of scores cluster around the mean in a normal distribution, adding or subtracting from a score closer to the mean will result in a ___ difference in percentile change than from a score on the edge

however, a percentile change on the ___ will result in a larger change in z score than close to the mean because the percentages are at smaller increments compared to the z scores out there

subtracting lowest score from the highest score

range is calculated by...

variance

standard deviation squared

standard deviation

a computed measure of how much scores vary around the mean score

square root

standard deviation is the __ of the variance

change, don't change

when a constant is added or subtracted to each data point, the measures of central tendency ___, measures of variability ___

change, change

when each data point is multiplied or divided by a constant, measures of central tendency ___, and measures of variability ___