Question

We are interested in the mean IQ score of seventh-grade girls in a Midwest school district. Here are the scores for 31 randomly selected seventh-grade girls in the district:
114 100 104 89 102 91 114 114 103 105
108 130 120 132 111 128 118 119 86 72
111 103 74 112 107 103 98 96 112 112 93
These scores follow a Normal distribution with standard deviation σ = 15. Treat these 31 girls as an SRS of all seventh-grade girls in this district. IQ scores in a broad population are supposed to have mean μ = 100. Is there evidence that the mean in this district differs from 100?

Answer 1

Here we have to test the claim that mean IQ of seventh grade girls in a Midwest school district is different than 100.

So first we have to find test statistic value and critical value

Then we have to compare both values , from that conclusion is drawn.