Question

In Jan – Feb 2005, a Gallup poll of 1012 children who are taking prescription medicine for Attention Deficit Disorder was taken. The survey asked if they think the medicine helped them. Gallup reports that 72% (assume 729 children) said that the medication did help. The report says that “For results based on this sample, one can say with 95% confidence that the maximum error attributable to sampling and other random effects is ±3 percentage points.”

: In Exercise B, suppose Gallup wanted a margin of error of 1% (0.01). How many children should they sample? Compute this number in two ways.

Do not assume any prior knowledge of the percent of children who would experience improvement.

Answer 1