Question

The Better Business Bureau settles 75% of complaints it receives involving new car dealers. Suppose a sample of 160 complaints involving new car dealers is selected. Find the probability that Better Business Bureau settles less than 129 of these complaints. (See exercise 39 on page 383 of your textbook for a similar problem.) Probability =

Answer 1

TOPIC:Normal approximation to the Binomial distribution.

= Define, p = P (of new complaints involving car dealers) = 0.75 ; n = sample size = 160 ; I dene p = 160 x 0.75 120 (75); and ri(1-6) = 160 x0, 25= 40 (25). So, we can use to the Binomial Normal approximation distribution here: ods I Let, x = No. of complaints received. do, xvN (= np, o2 = np (1-6)). (BY CLT). ex ww (82 = 120, 042 30) Now, we needs ayP (x 2129), =P ( x 2128.5). { using unity = P (x using Continuity conection 12. = (x + ( 286 25). √30 =P (Z < 1.5519). [2 mwco, ). - +7(1:5519). TEC) acdd y?) from Normal -10.9397 table) C3100,