A dietitian wishes to see if a person’s cholesterol level will change if the diet is
supplemented by a certain mineral. Six subjects were pretested, and then they
took the mineral supplement for a 6-week period. The results are shown in the
table. (Cholesterol level is measured in milligrams per deciliter.) Can it be
concluded that the cholesterol level has been changed at level of 0.10? Assume
the variable is approximately normally distributed.
subject 1 2 3 4 5 6
Before X1 210 235 208 190 172 244
After X2 190 170 188 173 228