Test theory and psychometrics Flashcards

1
Q

What must you know about a test to use it?

A
  • Name of test
  • Type of distribution
  • Definition of construct
  • Standardisation or raw?
  • Norms / cut offs / population
  • Evidence used to support measures - validity
  • M and SD
  • Out of
  • Experience of Tester
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2
Q

What is a distribution?

A

A set of test scores

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3
Q

What are raw scores?

A

unmodified scores of test performance

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4
Q

What is frequency distribution?

A

a tally of the number of score occurrences

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5
Q

What is a grouped frequency distribution?

A

Scores that fall within intervals are counted (95-99 etc.)

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6
Q

How can we describe the distribution of test scores?

A

Using:
measures of central tendency
measures of variability/ dispersion

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7
Q

What are the measures of central tendency?

A

mean, medium and mode

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8
Q

What are the measures of variability/ dispersion?

A

range, standard deviation

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9
Q

What does SD mean?

A

The average distance from the mean

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10
Q

What is used to develop norms?

A

Standard scores

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11
Q

What is a normative sample?

A

A group of people’s scores who are used as reference

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12
Q

Norms are?

A

test performance data for reference

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13
Q

What is a criterion?

A

A standard on which a judgement or decision is based: e.g. GPA x to get into a course

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14
Q

How many scores in a normal distribution fall above and below the mean?

A

50:50

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15
Q

How many scores in a normal distribution occur between the mean and 1 SD?

A

34%

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16
Q

How many scores in a normal distribution occur between +-1 SD? e.g. -1 SD to +1 SD

A

68% (34% on each side)

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17
Q

How many scores in a normal distribution occur between +-2 SD? e.g. -2 SD to +2 SD

A

96% (48% on each side)

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18
Q

How many scores in a normal distribution occur fall above 2SD?

A

2% (on each side)

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19
Q

How many scores in a normal distribution occur fall between 1SD and 2SD?

A

14% (on each side)

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20
Q

What does 75th percentile mean?

A

higher than 75% of people (in the top 25%)

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21
Q

What are the limitations of using percentiles?

A

changes all of the time
may not give an accurate reading
if ordinal data it looses precision

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22
Q

Why don’t we just give raw scores?

A

For broader meaning/ comparison

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23
Q

What is the simplest example of a standard score?

A

z score

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24
Q

What is the formula for calculating a z score?

A

z = x - mean / SD

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25
Q

What is the mean for a set of z scores?

A

0

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26
Q

What is the SD for a set of z scores?

A

1 SD

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27
Q

What does a z score tell us?

A

How many SD the raw score is below or above the mean

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28
Q

Other than a z score what is another type of standardised score?

A

t score

29
Q

What is the mean of a t score?

A

50 (half way between 0 and 100)

30
Q

What is the SD of a t score?

A

10

31
Q

What does a t score range between?

A

5 SD above and below the mean

e.g. 0 - 100

32
Q

IQ mean and SD?

A
M = 100 
SD = 15
33
Q

What does FSIQ stand for?

A

Full scale IQ

34
Q

Why, if reporting scores to parents is it better to use a t score than a z score?

A

No negatives (0-100 vs. -2 to 2)

35
Q

How do you calculate a t score?

A

T = (Z x 10) + 50

36
Q

How would you calculate a standardised score on the IQ test?

A

x = (z x SD) + Mean

37
Q

What does a true score assume?

A

That there is an ideal score that captures a degree of a construct

38
Q

What does test theory say about true scores?

A

They are not possible to obtain (measurement error)

39
Q

Test theory states someones x score =

A

True score + error

40
Q

What are some sources of error in test scores?

A
  • Test construction (validity, sample)
  • Test Administration (conditions, followed manual?, professionalism, computer used?, emotional state, relationship)
  • Scoring and interpretation (subjective responses)
41
Q

What could we assume if there was no error in test scores/

A
  • We’d get the same score twice
  • X would be the true score
  • Two parallel tests would get the same score
  • Wouldn’t need a range
42
Q

What is psychometrics?

A

The area of psychology interested in the quality of tests

43
Q

What makes a good test?

A

Validity and reliability

44
Q

What is validity?

A

supporting evidence for interpretation of scores

e.g. construct validity: measures what is is operationalised to measure

45
Q

Why is a measure of IQ iffy when it comes to validity?

A

Can you really use a number to represent how much of that construct (IQ) you have?

46
Q

What is a nomological network?

A

a collection of research surrounding and supporting the validity of a construct

47
Q

What are two types of construct validity?

A

Convergent: same as other tests measuring same construct
Discriminant: different to unrelated constructs

48
Q

How many factors in the Weschler?

A

4 cognitive domains

49
Q

What types of factor analysis are there?

A

Exploratory

Confirmatory

50
Q

What are 4 other types of validity (other than construct validity)?

A

face
content
population
criterion: predictive and concurrent

51
Q

What is predictive (criterion) validity?

A

Using a test to select the most adequate person (e.g. air force pilot that costs a lot to train - want to predict if they will stay)

52
Q

What is varamax rotation?

A

a way to figure out factors that are completely unrelated to each other (but not that useful)

53
Q

What type of analysis is usually used for confirmatory analysis?

A

SEM

54
Q

How is reliability assessed?

A

Correlation

55
Q

What are the 4 types of reliability?

A
  • Internal consistency (alpha: how well they hang together)
  • Test-retest (acceptable = .8)
  • Inter-rater
  • Parallel forms
56
Q

What is an example of something that could get good reliability but poor validity?

A

Using foot size to measure intelligence
• always get the same score
• not a good reflection of the construct IQ

57
Q

What is an example of something that could get good validity but poor reliability?

A

XXXX

needs to be valid to be considered reliable

58
Q

What is an example of something that could get good validity but poor utility?

A

Something that is too expensive

59
Q

What is an example of something that could get good utility but poor validity?

A

Myer briggs - questionable validity but useful for team building

60
Q

SEM stands for

A

standard error of measurement

61
Q

What is used because of the standard error of the mean?

A

Confidence intervals: e.g. 95% of the time, the true value will fall between x and x q

62
Q

How do you calculate confidence intervals?

A

CI = Score +-(1.96 x SEM)

63
Q

The larger the SE of the Mean?

A

The lower the reliability of the test

64
Q

How do you calculate the SEMeasurment?

A

SD sq root of 1-r

65
Q

If SD was 12 and r was .88 what would the SEMeasurment?

A

4.16

66
Q

What statistics do you use in a meta-analysis?

A

effect size and SE

67
Q

Why is height so easy to report?

A
  • Don’t have to rely on self report
  • Can observe directly
  • Have agreed definitions
  • Have agreed ways of measuring
68
Q

What are some different types of distributions?

A
normal 
bimodal 
positively skewed 
negatively skewed 
j-shaped
rectangular