Chapter 3 Flashcards
What is the term given to describe questions or tasks tat make-up a test?
Item
To give a test score meaning, test developers have resorted to what?
Norm referencing
Why has the use of norm referencing has been controversial in some circles?
Because the comparison process is thought to be demeaning it as having adverse motivational consequences. It says that the individual only has importance when considered in the context of other individuals
What are the two typical types of transformation of raw scores?
Linear - the addition of a constant to all raw scores
Non-linear - when the produced plot is not a straight line
What is the most common form of linear transformation?
z-score
What is the most common form of non-linear transformation?
Percentiles
What is the formula for a z-score?
Subtract the mean from the score and divide the result by the standard deviation (X - M / SD)
Why is a z-score useful?
Because if we can assume a distribution of scores is normal, the properties of the normal curve can be invoked in interpreting a z-score
Why are transformed scores not expressed as z-scores?
Because they are untidy numbers, with negative and positive signs, and decimal fractions following them
What is the most common form of interpretation of a score on a psychological test?
Comparing it with the scores that similar individuals obtain on the test
Z-scores were first applied to intelligence tests by who?
Wechsler
Why did Wechsler choose to set the mean for his deviation IQ at 100?
Because people thought from Binet’s test of intelligence that the average IQ was 100
Standardised scores have a mean of ___ and an SD of ___
10; 3
T-scores are used for what?
Expressing aggregate responses on each of the subscales of a teat
T-scores have a mean of ____ and an SD of ____
50; 10
A T-score of ____ or above is considered unusually high
65
Cattell’s variation of the Z-score for his 16 PF had a mean of ____ and an SD of____ and is called a ____ score
5.5; 2; sten
Just a note, don’t confuse percentile with percentage score
Y
What is a percentile equivalent?
The percentile score that expresses the raw score
What are the 3 ways that a percentile can be determined?
Graphic interpolation; arithmetic calculation; reading from the tables of the normal curve
How are normalised standard scores calculated?
By determining the percentiles for scores in the raw score distribution and then to calculate the Z-scores that correspond to the percentiles using the tables of a normal curve
The stamina scale has a mean of ____ and an SD of ____
5; approx 2
What is the stanine scale?
Breaks scores up into bands between 1-9 and groups them based on percentiles
There is a link between the linear and non-linear transformations of raw scores in popular use, and that link is the ____
Normal distribution
