The level o ead in he blood was determined or a sample o 152 male hazardous wast
ID: 3338446 • Letter: T
Question
The level o ead in he blood was determined or a sample o 152 male hazardous waste workers age 20-30 and also or sample u 86 emale workers, resulting in a mean ± standard error o 5.2 0.3 r te men and 3 ± 0.2 for the women. Calculate an estimate of the difference het een true average bloo ead levels for male and female workers away ha provides in i mation about re a an, precison (Use a 95% confidence interval. Round your answers to two decimal places.) Interpret the interval we are 95% confident that the true average blood lead level for male workers is less than that of female workers by an amount within the confidence Interval we are 95% confident that the true average blood lead level for male workers is greater than that of female workers by an amount outside the confidence interval. We are 95% confident that the true average hlood lead level for male workers is greater than that of female workers by an amount within the confidence interval We cannot draw a conclusion from the given information.Explanation / Answer
Calculation
Pooled Variance
s2p = (SS1 + SS2) / (df1 + df2) = 0.13 / 236 = 0
Standard Error
s(M1 - M2) = ((s2p/n1) + (s2p/n2)) = ((0/152) + (0/86)) = 0
Confidence Interval
1 - 2 = (M1 - M2) ± ts(M1 - M2) = 1.6 ± (1.97 * 0) = 1.6 ± 0.006
1 - 2 = (M1 - M2) = 1.6, 95% CI [1.594, 1.606].
You can be 95% confident that the difference between your two population means (1 - 2) lies between 1.594 and 1.606.
Option C. We are 95% confident that the true average blood lead level for male workers is greater than that of female workers by an amount within CI.