Asample 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).
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