Inspection of a random sample of 19 aircraft showed that 6 needed repairs to fix a wiring problem that might compromise safety.
(a) How large a sample would be needed to estimate the true proportion of jets with the wiring problem, with 99 percent confidence and an error of ± 4 percent? (Enter your answer as a whole number (no decimals). Use a z-value taken to 3 decimal places in your calculations.)