Question 7.91

91. Blood Lead Contamination. A study2 of workers in lead-exposed jobs found that the mean blood lead level was micrograms, with a standard deviation of micrograms. Let the sample size be . Assume the distribution is normal.

  1. Find the mean of the sampling distribution and the standard error .
  2. Calculate the probability that the sample mean blood lead level will be less than 27.85 micrograms.
  3. Compute .

7.1.91

(a) micrograms, micrograms (b) 0.1587

(c) 0.0228