Chapter 8

Problem 8-6

Problem 8-15 µ=60 σ=

Problem 8-15(contd.)

Problem 8-15(contd.)      x x x z   4 60   x x  

Problems 8-16 Since n=40,the sampling distribution of means will approximate a normal distribution

Problem 8-16(Contd.)

Problem

Problem minutes  n a x )320(.       x z xpb x x 

Problem 8-18(Contd.) )350320(.       x z xpc x 

Problem 8-18 contd..

=110,000 = 40,000/ 50 a. = / n = 40,000/ 50 = 5657 b. Normal distribution Problem 8-34

c ,000 X =110, Z P(X> 112,000)= =.3632 Problem 8-34 cont’d

d , Problem 8-34 cont’d P( X> 100,000)= =.9616 Z

e , ,000 X Problem 8-34 cont’d P(100,000<X< 112,000)= =.5984 Z

Problem Z )1.25(       xp n x z x 