1.IQ and Lead Exposure: Step 1The data set IQLEAD (found in the lab description) lists full IQ scores for a random sample of subjects selected from a group with low lead levels in their blood and another random sample of subjects selected from a group with high lead levels in their blood. The statistics are for these groups are summarized below.
Use a 0.05 significance level to test the claim that the mean IQ score of people with low lead levels is higher than the mean IQ score of people
with high lead levels.
Low Lead Level:n = 78, x̄= 92.88462, s = 15.34451
High Lead Level:n = 21, x̄ = 86.90476, s = 8.988352
Fill in the blanks to complete Step 1: The hypotheses:
H0μ1−μ2=
A.57 b.-57 c.0 D. 50
H1μ1−μ2 =
A. greater than B.less than C. not equal to
where μ1 is the mean from the low lead level group and μ2 is the mean from the high lead level group
2.IQ and Lead Exposure: Confidence Interval (cont) The data set IQLEAD (found in the lab description) lists full IQ scores for a random sample of subjects selected from a group with low lead levels in their blood and another random sample of subjects selected from a group with high lead levels in their blood. The statistics are for these groups are summarized below. Build 95% Confidence interval to test the claim that the mean IQ score of people with low lead levels is higher than the mean IQ score of people with high lead levels.
Fill in the blanks below to interpret the confidence interval.
Based on this sample, we are are [ Select ] A.95, B.5, C.1 D.99] % confident that the true difference in population mean IQ scores between the low lead group and the high lead group is between 1.34 and 10.62 posts. Since [ Select ] A.0, B.5, C.-5 is [ Select ] ["in", "not in"] in the interval, the sample evidence indicates a difference in IQ scores between the two groups.