Chap 4 Hw.docx - 4.21 A B P(5)=.1837 C P(2)=.0408 X P(x 2 3 4 5.0408.1735.6020.1837 D E(x)= 2.0408 3.1735 4.6020 5.1837)= 3.93 the average star rating

# Chap 4 Hw.docx - 4.21 A B P(5)=.1837 C P(2)=.0408 X P(x 2 3...

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4.21: A) B) P(5)= .1837 C) P(2)= .0408 D) E(x)= 2(.0408)+ 3(.1735)+ 4(.6020)+ 5(.1837)= 3.93; the average star rating is a 3.93 4.34: A) IQ score Invest Invest Probability No invest No invest Probability 1 893 0.020 4659 0.041 2 1340 0.030 9409 0.083 3 2009 0.045 9993 0.088 4 5358 0.120 19682 0.174 5 8484 0.190 24640 0.217 6 10270 0.230 21673 0.191 7 6698 0.150 11260 0.099 8 5135 0.115 7010 0.062 9 4464 0.100 5067 0.045 Investors: E(x)= 1(.020)+ 2(.030)+ 3(.045)+ 4(.120)+ 5(.190)+ 6(.230)+7 (.150)+ 8(.115)+ 9(.100)= 5.895 Non : E(x)= 1(.041)+ 2(.083)+ 3(.088)+ 4(.174)+ 5(.217)+ 6(.191)+7 (.099)+ 8(.062)+ 9(.045)= 4.992 ** 5.895> 4.992, therefore, investors have a higher IQ compared to non-investors 4.49: A) There is a fixed number of trials Two possible outcomes The probability of success remains the same from trial to trial The trials are independent The purpose would be to find the number of hotel guests who were delighted with their experience in 15 trials. B) 15% of guests were delighted, 80% of delighted guests would recommend again P(S)= .15(.80)=.12 or 12% were delighted and would recommend again  #### You've reached the end of your free preview.

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