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Ms. Hall gave her class a 10-question multiple-choice quiz.

LetX=the number of questions that a randomly selected student in the class answered correctly. The computer output gives information about the probability distribution of X. To determine each student鈥檚 grade on the quiz (out of 100), Ms. Hall will multiply his or her number of correct answers by 5and then add 50. Let G=the grade of a randomly chosen student in the class.

More easy quiz

a. Find the mean of G.

b. Find the range of G.

Short Answer

Expert verified

a. The mean is 88

b. The range ofGis30

Step by step solution

01

Part(a) Step 1 : Given Information    

Given :

X=the number of questions that a randomly selected student in the class answered correctly.

Ms. Hall multiplies his or her number of correct answers by 5and then add 50.

G=the grade of a randomly chosen student in the class.

02

Part(a) Step 2 : Simplification   

The grade is calculated by multiplying the number of right answers by 5and increasing by 50.

5X+50=G

This means that each data value in the Xdistribution is multiplied by the same constant 5and then multiplied by the same constant 50.

When the same constant is applied to each data value, the center of the distribution is also enlarged by the same constant.

Furthermore, if every data value is multiplied by the same constant, the distribution's center is multiplied by the same constant.

The mean is the center's measurement, as we all know.

As a result, the mean is increased by 50and multiplied by 5.

G=5X+50=5(7.6)+50=88

03

Part(b) Step 1 : Given Information    

Given :

X= the number of questions that a randomly selected student in the class answered correctly.

Ms. Hall multiplies his or her number of correct answers by 5and then add 50.

G=the grade of a randomly chosen student in the class.

04

Part(b) Step 2 : Simplification   

The range is defined as the difference between the maximum and least values.

As a result, for X, the range is

RangeX=Max-Min=10-4=6

The grade is calculated by multiplying the number of right answers by 5and increasing by 50.

5X+50=G

This denotes Every data value in the Xdistribution is multiplied by 5and then increased by50.

The spread of the distribution is unaltered if every data value is multiplied by the same constant.

Furthermore, if every data value is multiplied by the same constant, the distribution's spread is also multiplied by the same constant.

We know that the spread is measured by the range. As a result, the range is multiplied by five.

Thus, Range is :

RangeG=5(RangeX)=5(6)=30

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