Question

A normal distribution has a mean of µ = 70 with σ = 10. If one score is randomly selected from this distribution, what is the probability that the score will be greater than X = 82?

a.0.3849

b.0.7698

c.0.1151

d.0.8849

n a sample with M = 40 and s = 8, what is the z-score corresponding to X = 38?

a.–0.25

b.+ 0.25

c.0.50

d.–0.50

In a population of N = 10 scores, the smallest score is X = 8 and the largest is  X = 20. What is the range for this population?

a.10

b.12-13

c.8

d.20

For an exam with a mean of M = 74 and a standard deviation of s = 8, Mary has a score of X = 80, Bob’s score corresponds to z = +1.50, and Sue’s score is located above the mean by 10 points. If the students are placed in order from smallest score to largest score, what is the correct order?

a.Bob, Mary, Sue

b.Sue, Bob, Mary

c.Mary, Bob, Sue

d.Mary, Sue, Bob

Answer 1

1)

probability that the score will be greater than X = 82 =P(X>82)=P(Z>(82-70)/10)=P(Z>1.2)=0.1151

2)

z-score =(38-40)/8= -0.25

3)

range for this population =maximum-minimum=20-8=12

4)

\ Mary Score=80

Bob's score=74+1.5*8=86

Sue’s score =74+10=84

correct order: Mary, Sue, Bob