q02-f2008 - STA 4321/5325 Quiz 2 Name: KEY Mathematical...

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

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: STA 4321/5325 Quiz 2 Name: KEY Mathematical Statistics 1 Fall 2008 UF ID: 1. In responding to survey questions which concern sensitive topics people may not respond truthfully. Suppose that we plan to survey 12th graders and ask Have you tried marijuana? Assume that 40% of 12th graders who have tried marijuana will lie and respond no, and that 10% of those who have not tried marijuana will lie and respond yes. Assume also that 55% of all 12th graders have actually tried marijuana. A 12th grader is selected at random. (a) What is the probability that the person selected will answer yes to the question? (SET UP ONLY) (5 pts) M = { has tried marijuana } Y = { answers yes } N = { answers no } = Y P ( N | M ) = . 40 = P ( Y | M ) = . 60 P ( Y | M ) = . 10 P ( M ) = . 55 = P ( M ) = . 45 P ( Y ) = P ( M ) P ( Y | M ) + P ( M ) P ( Y | M ) = ( . 55)( . 60) + ( . 45)( . 10) = 0 . 375 (b) If the person selected answers yes, what is the probability that the person has actually...
View Full Document

This note was uploaded on 12/15/2011 for the course STA 4321 taught by Professor Staff during the Spring '08 term at University of Florida.

Page1 / 2

q02-f2008 - STA 4321/5325 Quiz 2 Name: KEY Mathematical...

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