Question

445 randomly selected light bulbs were tested in a laboratory, 316 lasted more than 500 30) hours. find a point estimate of the proportion of all light bulbs that last more than 500 hours.

Answer 1

Total number of bulbs tested, N = 445
Number of bulbs that lasted more than 500 hrs, x = 316

Point estimate of bulbs that lasted more than 500 hrs = x/N = 316/445 ≈ 0.71 = 0.71*100 = 71%