Excessive lead levels can negatively affect brain functions; lead poisoning is particularly dangerous to children. A study
Question:
The differences were found by calculating "factory child's lead level minus matched control child's lead level." Lead levels were concentrations in the blood, measured in micrograms per deciliter. A positive difference means the child of a factory worker has a higher lead concentration than the child in the control group. The data consisted of 1 tie (the same value for the child and the matching child), 28 pairs in which the factory worker's child had a higher level, and 4 pairs in which the factory worker's child had a lower level of lead.
Carry out a sign test to determine whether children whose parents are exposed to lead at work have a higher lead level than children whose parents are not exposed to lead at work. Use a significance level of 0.05 to see whether the experimental group had higher levels of lead.
Step by Step Answer:
Introductory Statistics Exploring The World Through Data
ISBN: 9780321978271
2nd Edition
Authors: Robert Gould, Colleen Ryan