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secure https//www.mathilcom/student PiayerHomework aspx?homeworkid questionid 18 flushed falses cida43220738ecenter win yes STAT 211 Section 022 Spring 2017 Homework: Chapter 15 Part 2 Score: 0.25 of 1 pt HW Score: 72 22% 6.5 of 15.1.61 Question Help Suppose that the IQs of university As students can be described by a normal model with mean 130 and standard deviation 8 points Also suppose that Kos of students from university Bcan be described by anorma model with mean 110 and standard deviaton 12. Select a student at random trom universiy A Fndthe probabilly that the student's IO is atleast 120 ponts The probablity (Round to three decimal places as needed b) select a student at random trom each school. Find he probability that he universiy A studentsia is at aast10ponts higher than the university B students io The probability is 0.755 (Round to three decimal places as needed Select 3 university B students at random Find tho probabiltylhat this group's average loisal east 115 ports. (Round to thion docmai places as needed Enter your answer in the answer box a then clickChock Answer

Explanation / Answer

here from normal distribution z=(X-mean)/std deviation

a) hence P(X>!20)=1-P(X<120)=1-P(Z<-1.25)=1-0.1056=0.8944

b)differnce of B-A =110-130=-20

and std deviation of differnce =(82+122)1/2 =14.422

hence P(B-A<-10)=P(Z<0.6933)=0.7560

c)here for 3 student of B; mean =110

std deviation =12/(3)1/2 =6.928

hence P(X>115)=1-P(X<115)=1-P(Z<0.7217)=1-0.7648=0.2352

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