A market analyst plans to determine the market share of an oat cereal, Cereal K, that is, the proportion of Cereal K sales among all sales of cereals. From data from several stores, the analyst finds that our of 420 cereal boxes sold, 126 were Cereal K.
a. Estimate the market share of Cereal K.
b. Estimate the standard error of your estimate in part a.
c Construct a 98% confidence interval for the population proportion.