Question

Inspection of a random sample of 35 aircraft showed that 24 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 98 percent confidence and an error of ± 6 percent? (Enter your answer as a whole number (no decimals). Use a z-value taken to 3 decimal places in your calculations.)
  
Sample size             

(b) Would the airline actually conduct further sampling, or just inspect all the planes?
  

• Conduct further sampling

• Inspect all the planes

Answer 1

Here

a. Now z value for 98% CI is 2.327 as P(-2.327<z<2.327)=0.98

Also E=0.06

So we will find n using formula of E

So

b. As sample size is large enough so

• Conduct further sampling