This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: CEE 304 Section 3 Problems Fall 08 1. Suppose a buffering solution with a concentration of 3.0 0.01 mg/L of ball bearings are normally distributed. You are told that the concentration of a buffering solution must be within 3.0 0.01 mg/L. No concentration outside this range is acceptable. You know from practice that concentrations have = 3.0 mg/L and = 0.005 mg/L. a.) On average, how many buffering solutions will be unacceptable? Ans. 4.56% b.) How many buffering solution concentrations fall within 1 standard deviation of the mean? Ans. 68.3% c.) What concentrations delineate the 95 th and 5 th percentile? Ans. X 0.95 = 3.0082, X 0.05 = 2.9918 2. Suppose the weekly demand for propane gas (in thousands of gallons) is a random variable X with pdf: 2 1 ( ) 2 1 f x x = for 1 x 2, and 0 otherwise a.) Show that it is a pdf. Ans. First must check if f ( x ) is defined for all x , which it is! Second, check if f ( x ) 0 for all x , which it is! Third, check if 2 1 ( ) 2 1 1 f x dx dx x + + = = , which it does!...
View
Full
Document
This note was uploaded on 10/13/2010 for the course CEE 3040 at Cornell University (Engineering School).
 '08
 Stedinger

Click to edit the document details