Question

) Lead concentrations in the egg shells of California condors have a mean of 1.8 ppm and a standard deviation of 0.5 ppm. The contamination levels of egg shells are classified as “low” if the lead concentration is below 1.0 ppm, “moderate” if the lead concentration falls
between 1.0 ppm and 2.4 ppm, and “high” the lead concentration is above 2.4. Assuming that the lead concentrations of egg shells follows a normal distribution, answer the following questions. (Hint* The categories of Low, Moderate, and High can help you identify the boundaries of each interval. For example, the boundaries of Low are −  to 1.0.)

13. What is the percentile of an egg shell with a lead concentration of 2.3 ppm? a. 82th b. 83th c. 84th d. 85th

14. What lead concentration corresponds to the 79th percentile? a. 2.2 ppm b. 2.5 ppm c. 2.6 ppm d. 2.7 ppm

15. What proportion of egg shells are predicted to fall into the “moderate” range? a. 0.65 b. 0.83 c. 0.67 d. 1.88

Answer 1