organic chemists often purify organic compounds by a method known as fractional crystallization. an experimenter wanted to prepare and purify 4.85 g of aniline. ten 4.85-gram specimens of aniline were prepared and purified to produce acetanilide. the following dry yields were obtained: 3.85, 3.88, 3.90, 3.62, 3.72, 3.80, 3.85, 3.36, 4.01, 3.82 construct a 95% confidence interval for the mean number of grams of acetanilide that can be recovered from 4.85 grams of aniline. assume that the obtained dry yields of acetanilide are i.i.d. and approximately normally distributed with an unknown mean and variance.