In 2003, the Gerber company sponsored a large random survey of the eating habits of American infants and toddlers. Among the many questions parents were asked was whether their child had eaten fried potatoes on the day before the interview. Of the 675 infants 9 to 11 months old in the study, 9% had eaten fried potatoes that day.

(a) 90% confidence interval for p: (0.072, 0.108)

(b) Which of the following assumptions are needed for the interval in (a) to be valid? Select all that apply

- The data are obtained randomly

- The original population is normally distributed

- The sample size is large enough so that the number of successes and the number of failures are both at least 15.

- The sample size is large enough so that the number of successes and the number of failures are both less than 15.