Question

Your statistics instructor administers a test having five multiple-choice items with four options each. List the ways in which one can guess correctly on exactly four items on this test.
Are there 24 ways, because: 4!
(4)(3)(2)(1) =24?

Answer 1

According to Science Daily, researchers have developed a new non-invasive technique which can accurately detect malignant melanoma without a biopsy. In their lifetimes 2.1% of Americans will develop malignant melanoma. The new test will correctly identify melanoma in 100% of cases where it is present, but gives a positive result in 9.1% of cases where it is not.