3. A chain of coffee shops wants to standardize the amount of caffeine in an 8 oz. cup of the dark roast coffee they sell, so they hire a lab to measure it. The lab receives 50 samples and determines that they have an average of 140 mg of caffeine per cup, with a standard deviation of 12 mg. A histogram of the sampled values approximately follows the normal curve. (a) We can infer that about 95% of the sampled cups had between mg and mg of caffeine. (b) For each range of caffeine values, find the approximate percentage of cups in the range. Less than 130 mg: % Between 130 and 150 mg: % More than 160 mg: % (c) What is the 90"1 percentile of the caffeine values? mg