Where did I make a mistake in my testing sample?
My testing sample includes 23 people classified as mentally retarded. I tested their IQs by a Weschler test. The control group is composed of 10 non-mentally-retarded people whose IQs I measured with the same test. The control group's combined IQ, however, came out low (less than 90), so where did I make a mistake?
By the way, this is all for my thesis titled "Analysis Dismorpholgy: Cariotipe and IQ of Local Area Mentally Retarded People Compared With Non-Mentally-Retarded people".
First, I belive your control group should be made up of the same number of subjects. Did you ONLY try the Weschler test or did you use another test too? Remember, some people are bad test takers. Did you happen to use an achievement test also?