Lecture 8

Question 1

To interpret test scores, scores have to be compared to one or more reference points, Flanagan distinguished four different types of reference points…

Answer 1

1. norm-referenced test score interpretation: test takers score is compared to other test takers
2. test-referenced test score interpretation: test takers score is compared to his scores on other tests or subtests
3. occasion-referenced test score interpretation: test takers test score is compared to his score from the same test from another occasion
4. criterion-referenced test score interpretation: test taker’s test score is compared to an external criterion or standard

Question 2

What means norm-referenced test score interpretation?

Answer 2

that the position of the test taker’s score is assessed with respect to the scores of the other test taker’s.

Question 3

Name 4 sampling methods

Answer 3

1. simple random
2. stratified random
3. cluster
4. judgemental sampling

Question 4

What is probability sampling?

Answer 4

simple random, stratified random and cluster sampling are probability sampling methods, and the generalization of sample characteristics to population characteristics is justified by probability theory

Question 5

What is non-probability sampling?

Answer 5

judgemental sampling is a form of non-probability sampling. generalization of the sample to the population can only be made by judgement, and not by probability theory

Question 6

What is stratified random sampling?

Answer 6

the population is split into non-overlapping strata. Then, randomly sample persons per stratum, with sample sizes according to proportion of persons in each stratum (=proportional allocation)

Question 7

What is cluster sampling?

Answer 7

simple random sampling of groups (clusters) of persons from a population of groups of persons. This can be done in two stages: one-stage cluster sampling-> clusters are randomly selected, and all persons of the selected clusters are tested.
two-stage cluster sampling -> clusters are randomly selected from a population of clusters, and only a simple random sample of persons from each cluster is tested, and so on.

Question 8

What is judgemental sampling?

Answer 8

persons are selected purposely and not by random selection.

Question 9

What is the difference between distribution shape-invariant transformations and distribution shape-enforcing transformations?

Answer 9

distribution shape-invariant transformations -> scale transformation that do not change the shape of the test score distribution
distribution shape-enforcing transformations -> transformations that enforce a shape on the distribution

Question 10

What is done by an distribution shape-invariant transformation?

Answer 10

these transformations transforms the original origin and unit of a scale to a new scale that has another origin and unit, but leaves the shape.

Question 11

How is the z-score transformation computed? (distribution shape-invariant transformation)

Answer 11

Zj = (TS - gemTS) / (s)

–> Standardized Z score = test score minus sample mean divided by the standard deviation of the test

Question 12

name to characteristics of Z-scores

Answer 12

1. mean = 0

2. SD = 1

Question 13

What is the general format of a linear transformation?

Answer 13

Yj = bXj + a

Yj = normed score of person j
Xj = raw score of person j
b = slope (sd)
a = intercept (mean)

Question 14

Name 3 common shape invariant transformations, along with their mean and SD

Answer 14

Type of transformation Mean SD
Z-score 0 1
T-score 50 10
IQ-score 100 15

Question 15

What is done by a distribution shape-enforcing scale transformation?

Answer 15

this transformation not only changes the mean and SD, but also changes the shape of the test score distribution.

The normed scores and raw scores have different distributions

Question 16

Name 4 common shape-enforcing scale transformations

Answer 16

1. percentile scores
2. decile scores
3. stanine scores
4. normalized scores

Question 17

What does a percentile score indicate?

Answer 17

the percentage of test takers who have a smaller test score

Question 18

What is the distribution of percentiles?

Answer 18

the percentile transformation enforce a uniform distribution of the test scores. A distribution that has an equal percentage of test takers per score.

Question 19

How is the decile score obtained?

Answer 19

by splitting the empirical frequency distribution into groups of 10%

Question 20

What is the distribution of the stanine scores?

Answer 20

the stanine scale transforms the test score distribution to a normal distribution

Question 21

What is test-referenced test score interpretation?

Answer 21

a test taker’s test or subtest score is compared to his scores on other tests and subtests. the score is interpreted within a test score profile

Question 22

What is occasion referenced test score interpretation?

Answer 22

a test taker’s score is compared with administrations of the same test on different occasions. The same test is administered to the same test taker on different occasions, and the test scores are compared.

Question 23

What is a response shift?

Answer 23

when the test taker recalibrates the item response scale from pretest to posttest

Question 24

Test scores at two measurement occasions are typically compared using …

Answer 24

a difference score:

Dj = S2j - S1j