Question

The average amount of money that people spend at Don Mcalds fast food place is $7.9700 with a standard deviation of $1.8100. 42 customers are randomly selected. Please answer the following questions, and round all answers to 4 decimal places where possible and assume a normal distribution. a. What is the distribution of X? X-NO b. What is the distribution of i? -NO c. What is the distribution of ? -NG d. What is the probability that one randomly selected customer will spend less than $7.91112 e. For the 42 customers, find the probability that their average spent is less than $7.9111. f. Find the probability that the randomly selected 42 customers will spend less than $332.2662. g. For part e) and f), is the assumption of normal necessary? Yes No h. The owner of Don Mcalds gives a coupon for a free sundae to the 5% of all groups of 42 people who spend the most money. At least how much must a group of 42 spend in total to get the free sundae? $

Answer 1

Of Xan11.97, 1.211 m-42 to ~ N17.97, 1 ) by centred lemet the by 142 =o. 2 y ex~ Nl 42+7.97 = 334.74 542x1.81 = 11-73) aj plx *7.911) = P1x=7.9] «7.547 2:57) _ =plz <-0-89 )-50.3173 el Pl TT 17.911) = P12 < -0.86 x 142) = 0.00lo A Plea, < 332.25 & 2) = P(x,-334-7433322000 Plz 2 - 2.4739) 1.81* ry Yes g] h. PlEXy) x) =0.05 = + 2x - 33434 20.gs = +1.68 11.73 & Ex= 315.45