In a sample of 100 Planter's Mixed Nuts, 19 were found to be almonds.
(a) Construct a 90 percent confidence interval for the true proportion of almonds.
(b) May normality be assumed? Explain.
(c) What sample size would be needed for 90 percent confidence and an error of ±0.03?
(d) Why would a quality control manager at Planter's need to understand sampling?