PDF4PRO ⚡AMP

Modern search engine that looking for books and documents around the web

Example: biology

Lecture 4: Random Variables and Distributions

Lecture 4: RandomVariables and DistributionsGoals Working with Distributions in R Overview of discrete and continuousdistributions important in genetics/genomics Random VariablesRandom Variables ! "01-1A rv is any rule ( , function) that associatesa number with each outcome in the samplespaceTwo Types of Random Variables A discrete Random variable has acountable number of possible values A continuous Random variable takes allvalues in an interval of numbersProbability Distributions of RVsDiscreteLet X be a discrete rv. Then the probability mass function (pmf), f(x),of X is:! f(x)=P(X = x), x 0,x Continuous! P(a"X"b)=f(x)dxab#Let X be a continuous rv. Then the probability density function (pdf) ofX is a function f(x) such that for any two numbers a and b with a b:abAaUsing CDFs to Compute ProbabilitiesContinuous rv:! F(x)=P(X"x)=f(y)dy#$x%pdfcdf! P(a"X"b)=F(b)#F(a)Using CDFs to Compute ProbabilitiesContinuous rv:! F(x)=P(X"x)=f(y)dy#$x%pdfcdf!

•This implies that until data is collected, any function (statistic) of the observations (mean, sd, etc.) is also a random variable •Thus, any statistic, because it is a random variable, has a probability distribution - referred to as a sampling distribution •Let’s focus on the sampling distribution of the mean,! X

Loading..

Tags:

  Distribution, Functions

Information

Domain:

Source:

Link to this page:

Please notify us if you found a problem with this document:

Spam in document Broken preview Other abuse

Transcription of Lecture 4: Random Variables and Distributions

Related search queries