To study the output of a machine that fills boxes with cereal, a quality control engineer weighed 150 boxes of Brand X cereal. The frequency distribution in the following table summarizes his findings. Find the mean weight of the boxes of cereal. (Use the midpoint of each interval. Round the answer to three decimal places.)
Mean weight

oz
x = Weight
(in ounces) Number of
boxes
15.3 ≤ x < 15.6 14
15.6 ≤ x < 15.9 22
15.9 ≤ x < 16.2 88
16.2 ≤ x < 16.5 18
16.5 ≤ x < 16.8 8