TP%2313_f08 - random variable = = = 85 . 85 . 85 . ) ( 85 ....

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
CE 3102 Fall 2008 Thought Problem 13 Speeds on a road are normally distributed, with a mean of 38 mph, and a standard deviation of 6 mph. What is the 85 th percentile speed on this road?
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
CE 3102 Fall 2008 Though Problem 13 Instructor’s Partial Solution Let X denote the speed of a randomly-selected vehicle on this road. The X is a normal random variable with mean = μ 38 mph and standard deviation σ =6 (mph). Let x .85 denote the 85 th percentile speed. By definition 85 . 0 ) ( 85 . = x X P Converting this probability statement to an equivalent one involving the standard normal
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: random variable = = = 85 . 85 . 85 . ) ( 85 . x Z P x X P x X P From the Table 6.1 of A&T (and interpolating) 85 . ) 0365 . 1 ( = Z P That is, 1.0365 and 85 . x both stand for the 85 th percentile point of the standard normal distribution. Equating and solving gives us mph x x 2 . 44 ) 6 )( 0365 . 1 ( 38 ) 0365 . 1 ( 0365 . 1 85 . 85 . + = + = =...
View Full Document

This document was uploaded on 02/05/2011.

Page1 / 2

TP%2313_f08 - random variable = = = 85 . 85 . 85 . ) ( 85 ....

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online