{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

class test

class test - 09/10 p 1 THE UNIVERSITY OF HONG KONG...

Info iconThis preview shows pages 1–3. 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 Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 09/10 p. 1 THE UNIVERSITY OF HONG KONG DEPARTMENT OF STATISTICS AND ACTUARIAL SCIENCE STAT1301 Probability and Statistics I Class Test Solution October 30, 2009 1. [10 marks] (a) State the definition of random variable . Ans: A random variable ℜ → Ω : X is a numerical valued function defined on a sample space. In other words, a number ( ) ω X , providing a measure of the characteristic of interest, is assigned to each outcome ω in the sample space. (b) Without using any mathematical expression, describe the memoryless property verbally. Ans: A nonnegative random variable has the memoryless property if when it is used to model the time of occurrence of an event, the fact that it hasn't happened yet, tells us nothing about how much longer it will take before it does happen, i.e. “the future is independent of the past”. P. T. O. 09/10 p. 2 2. [10 marks] A HIV test has a sensitivity of 99.7% and a specificity of 98.5%. Suppose that a subject, from a population with a 0.1% prevalence of HIV, receives a positive test result. What is the from a population with a 0....
View Full Document

{[ snackBarMessage ]}

Page1 / 4

class test - 09/10 p 1 THE UNIVERSITY OF HONG KONG...

This preview shows document pages 1 - 3. Sign up to view the full document.

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