Textbook Notes (363,559)
United States (204,628)
POS 3713 (7)
Chapter 6

# POS 3713 Chapter 6: K & W Chapter 6 Premium

2 Pages
31 Views

School
Florida State University
Department
Political Science
Course
POS 3713
Professor
William Berry
Semester
Spring

Description
6.3.1 The Normal Distribution Often called a “bell curve” Special properties of the Normal Distribution 1. It is symmetrical about the mean, such that the mode, media, and mean are the same 2. The normal distribution has a predictable area under the curve within speciﬁed distances of the mean (68-95-99 rule) 1 standard deviation in each direction = 68% of the area under the curve 2 (speciﬁcally 1.96) standard deviations in each direction = 95% of the area under the curve 3 standard deviations in each direction = more than 99% of the total area under the curve Frequency distribution: the distribution of actual scores in a sample (represents the frequency of each value of a particular variable) Questions we can answer using the normal distribution What can we say about a sample? Calculate the mean Add up all of the scores and divide by the total number Calculation: Ybar=(Sigma^nsub”i”=1Ysub”i”)/n Calculate the standard deviation SsubY=radical(Sigma^nsub”i”=1Ysub”i”(Ysub”i”-Ybar)^2)/(n-1) Sigma(Ysub”i”-Ybar)^2 means: for each observation, we subtract its value from the mean, then square that diﬀerence, then add up all deviations from the mean Sampling distribution: a hypothetical distribution of sample means The mean of the sampling distribution would be equal to the true population mean The standard deviation of the sampling distribution is: ThetasubYbar =ssubY/radical”n” “n” = sample size Standard error of the mean (“standard error”): the standard deviation of the sampling distribution of sample means; is equal to the sample standard deviation divided by the square root on the sample size ThetasubY = standard deviation/square root of all outcomes Conﬁdence interval: the conﬁdence a survey has about the likely location of the population mean 1st: choose a degree of conﬁdence (usually 95% or 2 standard deviations) Ybar plus/minus 2 x thetasubYbar Mean plus/minus (2 x standard error)
More Less

Related notes for POS 3713

OR

Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Join to view

OR

By registering, I agree to the Terms and Privacy Policies
Just a few more details

So we can recommend you notes for your school.