Medical experts advocate the use of vitamin and mineral supplements to help fight infections. A study undertaken by researchers at Memorial University recruited 96 men and women age 65 and older. One-half of them received daily supplements of vitamins and minerals, whereas the other half received placebos. The supplements contained the daily recommended amounts of 18 vitamins and minerals, including vitamins B-6, B-12, C, and D, thiamine, riboflavin, niacin, calcium, copper, iodine, iron, selenium, magnesium, and zinc. The doses of vitamins A and E were slightly less than the daily requirements. The supplements included four times the amount of beta-carotene than the average person ingests daily. The number of days of illness from infections (ranging from colds to pneumonia) was recorded for each person. Conduct a two-tail test and assume a 5\% level of significance. Assume that the 2 groups (i.e., supplements group and the placebo group) are approximately normally distributed with unknown but equal standard deviations. Calculate and provide the answers to the following information. H 0
: H 1
: test statistics = tcritical value = Can we infer that taking vitamin and mineral supplements daily increases the body's immune sustem?
