Question: Back injuries at work . A poll by the Gallup Organization sponsored by Philadelphia-based CIGNA Integrated Care found that about 40% of employees have missed work due to a musculoskeletal (back) injury of some kind. Let x be the number of sampled workers who have missed work due to a back injury.

a. Explain why x is approximately a binomial random variable.

b. Use the Gallop poll data to estimate p for the binomial random variable of part a .

c. A random sample of 10 workers is to be drawn from a particular manufacturing plant. Use the p from part b to find the mean and standard deviation of x , the number of workers who missed work due to back injuries.

d. For the sample in part c, find the probability that exactly one worker missed work due to a back injury. That more than one worker missed work due to a back injury.