An advertisement for the “30-in. Wonder” that appeared in the September 1983 issue of the journal Packaging claimed that the 30-in.

An advertisement for the “30-in. Wonder” that appeared in the September 1983 issue of the journal Packaging claimed that the 30-in. Wonder weighs cases and bags up to 110 lb and provides accuracy to within 0.25 oz. Suppose that a 50-oz weight was repeatedly weighed on this scale and the weight readings recorded. The mean value was 49.5 oz, and the standard deviation was 0.1. What can be said about the proportion of the time that the scale actually showed a weight that was within 0.25 oz of the true value of 50 oz? (Hint: Use Chebyshev’s Rule.)