Midterm 1 Flashcards
what is measurement
characteristic is defined and an instrument is selected to measure
statistic
provides a way to present a conglomeration of a set of raw scores
evaluation
take information and draw conglusion
forms of evaluation
diagnostic evaluation
formative evaluation
summative evaluation
continous scores
infinite number
measured with varying degree of accuracy
discrete scores
limited to specific numbers
not expressed as fractions
nominal measures
categorical
place people or things into categories
cannot be ranked along any dimensions
ordinal measure
rank people or things along some dimensions
no comparisons across different group rankings
interval measures
common unit of measurement
no true zero point
ratio measures
common unit of measurement
have a true zero point
standards for evaluation
norm-referenced standards
criterion-referenced standards
norm-referenced standards
set by national, local, regional data collection
determined by the # that the score is better than
criterion-referenced standards
set by national, regional and local data collection
passing criterion
EX
sum of scores
EX2
sum of the squared scores
(EX) 2
sum of the scores squared
n
N
sample
population
frequency distribution
most basic for of describing scores
table
X, f, cf in frequency distribution
X -> scores
f -> frequency
cf -> cumulative frequency
normal curve
bisymmetrical curve
50% on one side 50% on the other side
skewed curve
fewer scores to right or left of the curve
neg, skewed curve has fewer scores in neg direction
leptokurtic curve
many people scored the same score
platykuric curve
lots of scores have the same frequency
3 measures of central tendency
mode
median
mean
mode
most frequently occuring score
median
50th percentile score
50% falls below or above
mean
best measure of central tendency
average
what do measures of variability indicate
info about spread of the scores
measures of variability
range - reported with mode
semi-interquartile deviation (SID) - reported with median
standard deviation - reported with mean
what does standard deviation measure
variability and is reported with the mean
what does the SID measure
variability of the middle 50% of scores
what is norm referenced evaluation
comparison of your performance against a group
norms
predetermined performance standards
percentile ranks
describe the % of the group that falls below or abov the score
which percentile rank is the middle score
1st percentile rank -> median
what do percentile ranks tend to do
inflate the differences in the middle of the curve and deflate the differences in the extremes of the curve
what kind of measures are percentile scores
ordinal measures
what are standard scores used for
to standadize data
standard scores
z and T scores
Z scores
represent standard deviation units on the normal curve
run standard deviation of 1
from -3 to 3
T scores
mean = 50
run standard deviation of 10
from 20 - 80
