Researchers conducted a study to determine if magnets are effective in treating back pain. Subjects were divided into two groups, one given a treatment with real magnets, the other with fake magnets (placebo). Pain was measured using a scale such that higher values correspond to greater pain. Assume the distribution of pain measurements are Normal. Let µ₁ = mean pain level using real magnets and µ₂ = mean pain level using fake magnets.
A 95% confidence interval for μ₁ - μ₂ is found to be (-1.203, 0.186). Which conclusion is correct?
a. We cannot conclude that magnets are effective in treating back pain because the confidence interval contains 0.
b. We cannot conclude that magnets are effective in treating back pain because the confidence interval contains negative values.
c. We cannot conclude that magnets are not effective in treating back pain because the confidence interval contains 0.
d. We can conclude that magnets are effective in treating back pain because the confidence interval contains negative values.
e. We can conclude that magnets are effective in treating back pain because the confidence interval contains 0.
f. We can conclude that magnets are not effective in treating back pain because the confidence interval contains 0.