Question

Spring 2020 7. TQ tests have a mean score of 100 and a standard deviation of 15 Use these facts to answer the following questions (a) What is the proportion of people who score above 145 on IQ tests? (5 points) (b) A company hires only people who score in the top 20% (0.20) of IQ tests. Find the score a person must make to get a job with this company (4 points) (c) A company hires only people who score in the lower 30% (0.30) of IQ tests. Find the score a person must make to get a job with this company. (4 points) 8. For a standard normal distribution, find each of the probabilities below. (2 points each) (a) P(Z > 1.7) (b) P(Z <-0.5) (c) P(0.3<z<1.2)

Answer 1

Question 7.

A.

0.0014

B.

A person must make score 112.6 atleast to get the job, if company hires only top 20%

C.

A person must make score 107.8 atleast to get the job, if company hires top 30% only.

Quearion 8.

A.

0.0446

B.

0.3085

C.

0.2670

P(x > 145) = P x-1 . 145-100 l lo mis = P(No. 1) > 3) = 0.0013499 Plx > t ) = 0.2 PC X- M E - 100 = 0,2 - 15 = PIN co > = 0,2 t-10o 75 ) - t-100 15 0,84 I t= 112.6

) PLX k) = 0.3. e f ( x C4, Kaloo ) 2013 15 i n cost? > K-100 ) =0.3 15 k-100 15 0.52 k = 107.8 a) Plz 1.7 - 0.0445 65 b) Plz <-0.5) = p (z > 0.5) = 0.30854

C) (О 2 2 2 2 1 2 ) — Р( 2 ) о. 2) - P( 2 > 1. 2) Е о . 38 209 – о. | So - 0,26 o 2