A sample of 400 racing cars showed that 80 cars cost over $700,000. What is the 99% confidence interval of the true proportion of cars costing over $700,000
,q=0.8, n=400 (a,b)= *=.2+-(2.576*.02)=(.1485, .2515) We can say with 99% confidence that the proportion of cars costing over $700,000 is in the interval (.1485, .2515). Hope this helps!
