16:54 webwork.lakeheadu.ca No SIM HW2: Problem 16 Previous Problem Problem List

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16:54 webwork.lakeheadu.ca No SIM HW2: Problem 16 Previous Problem Problem List Next Problem (1 point) Suppose the scores of students on a Statistics course are Normally distributed with a mean of 414 and a standard deviation of 80. What percentage of the students scored between 254 and 414 on the exam? (Give your answer to 3 significant figures.) 0.4772 percent. Preview My Answers Submit Answers You have attempted this problem 2 times. Your overall recorded score is 0%. You have 2 attempts remaining Email instructor Page generated at 07/27/2018 at 09:54am EDT WeBWorK © 1996-2017] theme: math4 ww-version: WeBWork-2.13 pg version PG-2.13 The WeBWorK Project

Explanation / Answer

Solution16:

mean=414

sd=80

P(254<X<414) to be found

P(X<414)-P(X<254)

Rcode to get answer is

pnorm(414,mean=414,sd=80) -pnorm(254,mean=414,sd=80)

0.4772499

But it is asking in percetages

0.4772499*100

=47.72499

=47.725%

ANSWER:47.725

Solution17:

P(-7<X<20)

P(X<20)-P(x<-7)

By Hit and trial method in R for various values of mean we got

pnorm(20,mean=6.195,sd=6.195) -pnorm(-7,mean=6.195,sd=6.195)

we are getting the area

0.9704853

MEAN=6.195

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