If a light bulb manufacturing company wants to​ estimate, with 95​% confidence, the mean life...

Question

If a light bulb manufacturing company wants to​ estimate, with 95​% confidence, the mean life of compact fluorescent light bulbs to within ±225 hours and also assumes that the population standard deviation is 900

​hours, how many compact fluorescent light bulbs need to be​ selected?

n=?



​(Round up to the nearest​ integer.)  

Answer 1

n = (z-critical * s/E)**2 = (1.96*900/225)**2 = 61.47 ~ 62