Some people think using magnets can reduce back pain. Two groups of people suffering from back pain are given treatments to test this theory, one group is treated with magnets and the other group is treated with nonmagnetic pieces of metal. Reduction in pain is measured with a scale from 0 to 1, where the larger the number, the larger the pain reductions. Below is a summary of the results: Magnets Nonmagnetic Sample Size 20 20 Sample Mean 4.7 4.4 Sample Standard Deviation s 1.2 1.4 a. Find a 90% confidence interval for the differences in the mean pain reduction.
b. Is there evidence that Magnets help reduce back pain?