transforming scores changing the scale of the data in some way. change each score
TRANSCRIPT
Transforming Scores
• Changing the scale of the data in some way.
• Change each score.
• converting cm. to inches
• comparing values on different scales (e.g., height and weight)
• percentiles
Percentiles:
converting data into the % of people at or below a particular level.
Example:
Class A: score of 80
Class B: score of 55
Class A
98 1
96 2
88 2
85 3
82 2
80 2
76 3
72 3
70 2
Class B:
60 1
55 2
54 2
51 4
48 3
40 5
37 3
100
n
cfpercentile
Class A cf
98 1
96 2
88 2
85 3
82 2
80 2
76 3
72 3 5
70 2 2
Class A cf
98 1
96 2
88 2
85 3
82 2
80 2 10
76 3 8
72 3 5
70 2 2
Class A cf
98 1 20
96 2 19
88 2 17
85 3 15
82 2 12
80 2 10
76 3 8
72 3 5
70 2 2
10020
10
percentile
1005.percentile
%50%
Class B: cf
60 1
55 2
54 2
51 4
48 3
40 5 8
37 3 3
Class B: cf
60 1
55 2 19
54 2 17
51 4 15
48 3 11
40 5 8
37 3 3
Class B: cf
60 1 20
55 2 19
54 2 17
51 4 15
48 3 11
40 5 8
37 3 3
10020
19
percentile
%95%
Z score:
transforms raw data into distance from the mean in units of standard deviation
s
xxz
Your score was 80 in a class with a mean of 79 and a standard deviation of 4.
4
7980 z