6.39 DXA scanners. A dual-energy X-ray absorptiometry (DXA) scanner is used to measure bone mineral density for people who may be at risk for osteoporosis. One researcher believes that her scanner is not giving accurate readings. To assess this, the researcher uses an object called a “phantom” that has known mineral density μ = 1.4 grams per square centimeter. The researcher scans the phantom 10 times and compares the sample mean reading with the theoretical mean μ using a significance test. State the null and alternative hypotheses for this test.