In a certain region, prepackaged products labeled 500 g must contain on average at least 500 grams of the product, and at least 90% of all packages must weigh at least 490 grams. In a random sample of 300 packages, 288 weighed at least 490 grams. a. Give a point estimate of the proportion of all packages that weigh at least 490 grams. b. Verify that the sample is sufficiently large to use it to construct a confidence interval for that proportion. c. Construct a 99.8% confidence interval for the proportion of all packages that weigh at least 490 grams