PSYC332 mid sem

Question 1

Reliability?

Answer 1

Consistency - will get the same score on two occasions

Question 2

Rxx?

Answer 2

Correlated scores of one administration of the test with scores on another administration of the exact same test (same variable being correlated)

Question 3

Reliability coefficient for a good test?

Answer 3

At least .8

Question 4

Test-retest?

Answer 4

Identical test given to the same group of people on two occasions
Coefficient of stability

Question 5

Test-retest error variance?

Answer 5

Time sampling

Question 6

Alternative forms?

Answer 6

Two versions of the test which are constructed in an identical way but the content is slightly different

Can be given immediately after one another or can be given on different days (this is delayed)

correlation of equivalence

Question 7

Alternate forms error variance?

Answer 7

Content sampling

Delayed alternative forms - time sampling

Question 8

Internal consistency reliability?

Answer 8

Split-half
KR20
Coefficient alpha

Question 9

Split-half reliability?

Answer 9

calculated easy and doesn’t require administering two different forms or on two different occasions.

Single test is administered and the test is split into two halves – score on two halves for those individuals is correlated

correlation of consistency

Question 10

Split -half reliability error variance?

Answer 10

content sampling

Underestimates reliability because the longer the test is, the higher reliability coefficient will be.

Question 11

Spearman brown formula?

Answer 11

Determines how much split-half reliability underestimates the reliability coefficient

Question 12

KR20?

Answer 12

Single test administration
Used for dichotomously scored items
Value = equal to the mean value of all- split half coefficients for a test.

Question 13

Coefficient alpaha?

Answer 13

Single test administration
Multiple choice test or Likert
Value = equal to the mean value of all- split half coefficients for a test.

Question 14

Error variance KR20 and alpha?

Answer 14

Content sampling
heterogeneity of the behaviour domain being sampled
Maths test example: maths test that only has addition problems in it = homogeneity- same throughout. If a test has different mathematical concepts e.g. addition, subtraction, algebra, division = heterogeneity. The greater amount of differences in what you’re measuring i.e. the more heterogeneity a test has the less internal consistency the test will have.

Question 15

Pearson’s R and homogeneity?

Answer 15

r decreases as homogeneity of the sample increases – know with Pearson’s r that the more similar a sample is the lower the correlation coefficient.

If the standardised sample is varied i.e. Heterogenous (people are not as similar) correlation will be higher.

Question 16

Validity?

Answer 16

Accuracy - is the test measuring what we think it’s measuring

Question 17

Rxy?

Answer 17

x = the test being measured and y = something else being measured to see if the test correlates with the other thing that is being measured

Question 18

Face validity?

Answer 18

The test appears to be testing what it sets out to test. It has no rxy, but it is important for most tests as it helps with compliance of test takers and makes them less suspicious. However, don’t want it to be too face valid where the test taker can manipulate the answers because they know what the test is assessing.

Question 19

Criterion validity?

Answer 19

he test scores “predict” performance
Assessing future statistical performance!

Test scores are compared with performance on a criterion that is a direct and independent measure of what the test is designed to measure

Question 20

Criterion, predictive validity?

Answer 20

Test is given to a group of people at one point in time – then at another point the same group of people are measured using the same criterion. Tells us whether test scores accurately predict criterion and whether they are valid indicators of criterion performance at some later point in time.

Question 21

Good level of validity?

Answer 21

Looking for a statistically significant correlation coefficient of approximately 0.2 to 0.5.

Question 22

Criterion, concurrent validity?

Answer 22

Concurrent = the most appropriate when looking at tests that are diagnosing the current state. Administration of the test and scores are obtained at the same time

Question 23

Factors that influence rxy

Answer 23

Low sample size will impact on statistical significance

Restriction of range in either the rest or criterion scores – correlation will be reduced e.g. Only looking at high scores reduces the correlation as it looks more circular rather than cigar shaped (selectivity problem = especially effected). Lower rxy if you restrict the range.

Non-linear relationship between test scores and criterion scores – assumes x + y = linear therefore non- linear = affect the correlation.

Problems with criterion – biggest issues, the test may be good but operationalising criterion = not good.

Question 24

Content validity?

Answer 24

Not empirical no rxy
Making sure the items on the test tap into the range of behaviours we want to measure

most relevant for achievement tests.

attempts to sample full behaviour domain

Built into the test from the outset

Question 25

Construct validity?

Answer 25

The degree to which test scores reflect individual differences on a psychological construct i.e. Something that is not directly observable like anxiety

Needs lots of studies to test – get a gradual accumulation of data about the test.

Ask whether test scores behave the same way that we expect given knowledge of the construct