Question

In a study of the accuracy of fast food? drive-through orders, Restaurant A had 225 225 accurate orders and 60 60 that were not accurate. a. Construct a 95 95?% confidence interval estimate of the percentage of orders that are not accurate. b. Compare the results from part? (a) to this 95 95?% confidence interval for the percentage of orders that are not accurate at Restaurant? B: 0.183 0.183 less than

Answer 1

Result:

In a study of the accuracy of fast food? drive-through orders, Restaurant A had 225 accurate orders and 60 that were not accurate.

a. Construct a 95?% confidence interval estimate of the percentage of orders that are not accurate.

Proportion not accurate = 60/(60+225) =0.210526

Confidence Interval Estimate for the Proportion
Data
Sample Size	285
Number of Successes	60
Confidence Level	95%
Intermediate Calculations
Sample Proportion	0.210526316
Z Value	1.9600
Standard Error of the Proportion	0.0241
Interval Half Width	0.0473
Confidence Interval
Interval Lower Limit	0.1632
Interval Upper Limit	0.2579

95% CI for proportion= (0.1632, 0.2579)

95% CI for percentage= (16.32, 25.79)