The weight of thousands of snack bars produced by a food company has a normal distribution with a mean of 147.1 g and standard deviation of 12.3 g. a. if the company labels 150.0 g on all the individual wrappers, what percent of bars are lighter than advertised? b. what percent of bars are between 140 and 150 g? c. what weight should be labeled on the wrappers so that only 5% of the bars are underweight? d. between what values do the middle 75% of the weights of the bars lie?