Question:
A study reported in the American Journal of Public Health (Science News)-the first to follow blood lead levels in law abiding handgun hobbyists using indoor firing ranges-documents a significant risk of lead poisoning. 4 Lead exposure measurements were made on 17 members of a law enforcement trainee class before, during, and after a 3-month period of firearm instruction at a state-owned indoor firing range. No trainee had elevated blood lead levels before the training, but 15 of the 17 ended their training with blood lead levels deemed "elevated" by the Occupational Safety and Health Administration (OSHA). If the use of an indoor firing range causes no increase in blood lead levels, then p, the probability that a person's blood lead level increases, is less than or equal to .5. If, however, use of the indoor firing range causes an increase in a person's blood lead levels, then p > .5. Use the sign test to determine whether using an indoor firing range has the effect of increasing a person's blood lead level with α = .05.