An office supply company conducted a survey before marketing a new paper shredde
ID: 3310560 • Letter: A
Question
An office supply company conducted a survey before marketing a new paper shredder designed for home use. In the survey, 80% of the people who tried the shredder were satisfied with it. Because of this high satisfaction rate, the company decided to market the new shredder. Assume that 80% of all people are satisfied with this shredder. During a certain month, 100 customers bought this shredder. Find the probability that of these 100 customers, the number who are satisfied is 69 or fewer. Round your answer to four decimal places. The probability is
Explanation / Answer
here expected number of satisfied people =np =100*0.80 =80
and std deviaiton =(np(1-p))1/2 =4
therefore probability that of these 100 customers, the number who are satisfied is 69 or fewer =P(X<=69)
=P(Z<(69.5-80)/4) =P(Z<-2.625)=0.0043