Lowbirth weight babies are at increased risk of respiratory infections in the first few months of life and have low liver stores of vitamin A. In a randomized, double-blind experiment, 130 lowbirth weight babies were randomly divided into two groups.
Subjects in group 1 (the treatment group, n1 = 65) were given 25,000 IU of vitamin A on study days 1, 4, and 8 where study day 1 was between 36 and 60 hours after delivery. Subjects in group 2 (the control group, n2 = 65) were given a placebo.
The treatment group had a mean serum retinol concentration of 45.77 micrograms per deciliter (μg/dL), with a standard deviation of 17.07 μg/dL. The control group had a mean serum retinol concentration of 12.88 μg/dL, with a standard deviation of 6.48 μg/dL. Does the treatment group have a higher standard deviation for serum retinol concentration than the control group at the α = 0.01 level of significance? It is known that serum retinol concentration is normally distributed.