Question

The medical records of infants delivered at Kaiser Memorial Hospital show that the intents' lengths at birth (in inches) are normally distributed with a mean of 19 and a standard deviation of 2.2. Find the probability that an infant selected at random from among those delivered at the hospital measures the following. (Round your answers to four decimal places) (a) more than 20 in (b) less than 18 in. (c) between 17 and 21 in. You may need to use the appropriate table in the Appendix of Tables to answer this question

Answer 1

Given distribution follows normal with mean u = 19 and standard deviation o = 2.2 a) P(more than 20) = P(x>20) = P(**> 2072) =P(Z> 0.45) =1-P(Z<0.45) =1-0.6736 (using appendix table) =0.3264 b) P(less than 18) = P(x<18) = P(**< 19:29) =P(Z< -0.45) = 0.3264 (using appendix table)

c) P(between 17 and 21) = P(17<x< 21) = P(47=29 < * < 22:29) =P(-0.91<z<0.91) =P(z<0.91)-P(z<-0.91) = 0.8186-0.1814 = 0.6372 (using appendix table)