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Get Full Access to Mathematical Statistics With Applications - 7 Edition - Chapter 4 - Problem 74e
Get Full Access to Mathematical Statistics With Applications - 7 Edition - Chapter 4 - Problem 74e

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# Scores on an examination are assumed to be normally ISBN: 9780495110811 47

## Solution for problem 74E Chapter 4

Mathematical Statistics with Applications | 7th Edition

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Problem 74E

Problem 74E

Scores on an examination are assumed to be normally distributed with mean 78 and variance 36.

a What is the probability that a person taking the examination scores higher than 72?

b Suppose that students scoring in the top 10% of this distribution are to receive an A grade. What is the minimum score a student must achieve to earn an A grade?

c What must be the cutoff point for passing the examination if the examiner wants only the top 28.1% of all scores to be passing?

d Approximately what proportion of students have scores 5 or more points above the score that cuts off the lowest 25%?

e Applet Exercise Answer parts (a)–(d), using the applet Normal Tail Areas and Quantiles.

f If it is known that a student’s score exceeds 72, what is the probability that his or her score exceeds 84?

Step-by-Step Solution:

a

Step 1: Goal

To find the probability that a person taking the examination scores higher than 72.

Step 2 of 4

Step 3 of 4

##### ISBN: 9780495110811

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