a study is designed to test whether there is a difference in mean daily calcium intake (mg/day) in three groups of adults aged 60-70 years old: (i) those with normal bone density, (ii) those with osteopenia, a low bone density which may lead to osteoporosis, and (iii) those with osteoporosis, which is a severe reduction in bone density that can lead to frequent fractures. hospital records are used to collect daily calcium intake on 20 patients in each of the three bone density groups (60 total people). means and standard deviations (sd) for calcium intake were: