Question

Suppose the heights of 18-year-old men are approximately normally distributed, with mean 66 inches and standard deviation 1 inches.

(a) What is the probability that an 18-year-old man selected at random is between 65 and 67 inches tall? (Round your answer to four decimal places.)


(b) If a random sample of twenty 18-year-old men is selected, what is the probability that the mean height x is between 65 and 67 inches? (Round your answer to four decimal places.)

Answer 1

classmate Date Pege deta denote 18-year old XNN 166,0 man's height PL 658 x< 67 ) E PC - SBS) P C12(<1) Using Normal P( 65CX (67) = = 0 (65-66 x-66 < 67-66) where Zunion Plz<)- P( 2<-1) prob. Table we get 0.6826_ E: P12<10=0.8413) EFLX) = 66 "IF XN NI 66,1) then n=20 - E(X)= E xi) = T V(x) = on ho | x − ( 6 6, 720) P P( 65 <* <67) : pl 65-66 ex- 66 <61-66) I Tho Tho Sw) p/-4.412 5 2 24.412 | since fou nomal Diser TPC 12) (3) = 1