Determine whether the given description corresponds to an observational study or an experiment. In a study of 378 women with a particular disease, the subjects were injected with vitamins to determine if the vitamins have an effect on the disease. Does the given description correspond to an observational study or an experiment?

The weights of players in a basketball league are distributed normally. the distance (d) of each player's weight (w) from the mean of 86 kilograms was computed as follows: d = |w - 86| if d is greater than 7 for approximately 5% of the players, what is the approximate standard deviation of the players' weights? a. 1.75 kilograms b. 3.5 kilograms c. 4.3 kilograms d. 7 kilograms