Validity & Reliability
by Dee Sandberg
1. Semi-interquartile range (SIQR)
1.1. organize numerically
1.2. add two middle numbers together and divide by 2
1.2.1. one half the schore in a distribution
1.2.1.1. accompanies a median
2. Standard Deviation
2.1. SD
2.2. most accurate measure
2.2.1. includes all scores in computation
2.2.1.1. estimate of variability/accompanies the mean
2.3. score deviation (X-M)
3. Normal Distribution
3.1. symmetrical distribution
3.1.1. represents mathematical properties
3.2. standard binet IQ scores
3.3. in curve the mean, median, mode coincide (normal)
4. Range
4.1. Subtract the lowest score from the highest score
4.2. Example: 11,11,11,11,12,12,13,14,14,14,15,15,15,15,16,17,18,18,18 Subtract: H-L(18-11 = 7) (Kubiszyn, Borich, 2010)
5. Converted Scores
5.1. test scores as percentages
5.1.1. Raw scores not interpretable
5.2. Raw scores
5.2.1. Psychology
5.2.1.1. history
5.3. add mean
5.3.1. means and standard deviation