Question

Not all dust particles that are in the air cause problems to our lungs. Part of the study measured the respirable dust in 115 drill and blast workers to 220 outdoor concrete workers. For drill and blast workers, the mean exposure to respirable dust particles was 6.3 mg.y/m3 with a standard deviation of 2.8 mg.y/m3. The corresponding values for the outdoor concrete workers were 1.4 mg.y/m3 and 0.7mg.y/m3.
(a) Calculate and interpret a 99% confidence interval for the true difference in mean exposure between drill and blast workers and outdoor concrete workers.

(b) Does the data provide significant evidence that drill and blast workers have higher mean exposure to respirable dust?

Answer 1