Based on the chart your class has completed, it is plausible that 60% is the percentage of the population that are right-eye dominant? What percentages are plausible? These percentages are called the 90% confidence interval.
Use your completed chart to find these confidence intervals.
a. Suppose that a random sample of 40 toddlers finds that 34 know what color Barney is. What is the 90% confidence interval for the percentage of toddlers who know what color Barney is?
b. Suppose that a random sample of 40 adults finds that 10 know what color Barney is. What is the 90% confidence interval for the percentage of adults who know what color Barney is?
c. Observe 40 students on your campus. Find the 90% confidence interval for the percentage of students who carry backpacks.