SOLUTION: Here are the IQ test scores of 31 seventh-grade girls in a Midwest school district: 72, 74, 86, 89, 91, 93, 96, 98, 100, 102, 103, 103, 103, 104, 105, 107, 108, 111, 111, 112, 112

Question 1036043: Here are the IQ test scores of 31 seventh-grade girls in a Midwest school district:
72, 74, 86, 89, 91, 93, 96, 98, 100, 102, 103, 103, 103, 104, 105, 107, 108, 111, 111, 112, 112, 112, 114, 114, 114, 118, 119, 120, 128, 130, 132
What proportions of the scores are within one standard deviation of the mean?
What proportions of the scores are within one standard deviation of the mean?
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
The mean is 105.8 and the sd of the sample (I think this is a sample) is 14.3
Between 1 sd of the mean would include (91.5,120.1) or (92,120). That is 23/31 scores.
If the second part is 2 sd s of the mean (not written as such), it would be the interval (77.2,132.4) or (78,132). That would be 29/31 scores.
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