Chi-Square Test Section 12.1.

Slides:



Advertisements
Similar presentations
Chi-Square Test Section Categorical Variables Based on observations Univariate – single categorical variable  Example: Sample 100 people & ask.
Advertisements

Chapter 11 Other Chi-Squared Tests
Chi-square test Chi-square test or  2 test. Chi-square test countsUsed to test the counts of categorical data ThreeThree types –Goodness of fit (univariate)
AP Statistics Tuesday, 15 April 2014 OBJECTIVE TSW (1) identify the conditions to use a chi-square test; (2) examine the chi-square test for independence;
Chi-Square Test. Most of the previous techniques presented so far have been for NUMERICAL data. So, what do we do if the data is CATEGORICAL? Ex: Information.
The Chi-Square Test for Association
CHI-SQUARE GOODNESS OF FIT TEST u A nonparametric statistic u Nonparametric: u does not test a hypothesis about a population value (parameter) u requires.
Chapter 13 Chi-Square Tests. The chi-square test for Goodness of Fit allows us to determine whether a specified population distribution seems valid. The.
For testing significance of patterns in qualitative data Test statistic is based on counts that represent the number of items that fall in each category.
Chapter 11: Applications of Chi-Square. Count or Frequency Data Many problems for which the data is categorized and the results shown by way of counts.
Chi-square test or c2 test
1 Chi-Square Heibatollah Baghi, and Mastee Badii.
Chapter 16 – Categorical Data Analysis Math 22 Introductory Statistics.
Chapter 26 Chi-Square Testing
Copyright © Cengage Learning. All rights reserved. 11 Applications of Chi-Square.
Chapter 14: Chi-Square Procedures – Test for Goodness of Fit.
The Practice of Statistics Third Edition Chapter (13.1) 14.1: Chi-square Test for Goodness of Fit Copyright © 2008 by W. H. Freeman & Company Daniel S.
Chapter 13 CHI-SQUARE AND NONPARAMETRIC PROCEDURES.
Section 12.2: Tests for Homogeneity and Independence in a Two-Way Table.
Copyright © 2013, 2009, and 2007, Pearson Education, Inc. Chapter 11 Analyzing the Association Between Categorical Variables Section 11.2 Testing Categorical.
Chapter 13- Inference For Tables: Chi-square Procedures Section Test for goodness of fit Section Inference for Two-Way tables Presented By:
Chi Square Test for Goodness of Fit Determining if our sample fits the way it should be.
Comparing Observed Distributions A test comparing the distribution of counts for two or more groups on the same categorical variable is called a chi-square.
Test of Goodness of Fit Lecture 41 Section 14.1 – 14.3 Wed, Nov 14, 2007.
Comparing Counts Chi Square Tests Independence.
Basic Statistics The Chi Square Test of Independence.
Ch 26 – Comparing Counts Day 1 - The Chi-Square Distribution
Other Chi-Square Tests
Test of independence: Contingency Table
Chi-Square (Association between categorical variables)
CHAPTER 26 Comparing Counts.
Chi-Square hypothesis testing
CHAPTER 11 Inference for Distributions of Categorical Data
Unit 8 Section 7.5.
Chi-square test or c2 test
Chi-squared test or c2 test
Test for Goodness of Fit
Chi-Squared Goodness of Fit
X2 = M T W F P-Value = CONDITIONS
Chi-square test or c2 test
1) A bicycle safety organization claims that fatal bicycle accidents are uniformly distributed throughout the week. The table shows the day of the week.
Goodness of Fit Tests The goal of χ2 goodness of fit tests is to test is the data comes from a certain distribution. There are various situations to which.
Chapter 11 Goodness-of-Fit and Contingency Tables
Elementary Statistics: Picturing The World
Chapter 3 Graphical and Tabular Displays of Data.
The Analysis of Categorical Data and Chi-Square Procedures
Different Scales, Different Measures of Association
Chi Square Two-way Tables
Lecture 18 Section 8.3 Objectives: Chi-squared distributions
Chi-Square Goodness-of-Fit Tests
Contingency Tables: Independence and Homogeneity
Lecture 36 Section 14.1 – 14.3 Mon, Nov 27, 2006
Overview and Chi-Square
15.1 Goodness-of-Fit Tests
Inference for Relationships
Chi-square test or c2 test
Inference for Tables Chi-Square Tests Ch. 11.
The Analysis of Categorical Data and Goodness of Fit Tests
Lecture 41 Section 14.1 – 14.3 Wed, Nov 14, 2007
Analyzing the Association Between Categorical Variables
Non-Parametric Statistics Part I: Chi-Square
The Analysis of Categorical Data and Goodness of Fit Tests
Parametric versus Nonparametric (Chi-square)
The Analysis of Categorical Data and Goodness of Fit Tests
Inference for Tables Chi-Square Tests Ch. 11.
The Analysis of Categorical Data and Goodness of Fit Tests
13.1 Test for Goodness of Fit
Chapter Outline Goodness of Fit test Test of Independence.
Chapter 11 Lecture 2 Section: 11.3.
Presentation transcript:

Chi-Square Test Section 12.1

Categorical Variables Based on observations Univariate – single categorical variable Example: Sample 100 people & ask if they agree or disagree with a question. Bivariate – uses two categorical variables Example: Sample 100 people & ask if they are male/female and what political party they support.

One-Way Frequency Table - univariate Democrat Independent Republican Data Vertical One-Way Table Horizontal One-Way Table   Freq. Democrat 4 Republican 6 Independent 2   Democrat Republican Independent Freq. 4 6 2

Goodness of Fit Test Used to measure the extent to which the observed counts differ from the expected counts. K = # categories of a catagorical variable Df = k – 1 Test Statistic:

Assumptions Observed Values are based on random Samples Sample size is large – each cell count is at least 5.

Hypotheses Ho: State each proportion’s hypothesized value. HA: At least 1 of the proportions differ from the hypothesized value.

It uses the Chi-Square Chart Positively Skewed Uses d.f. On calculator!

Is there a preference in type of car?   Freq. Expected SUV 27 Truck 25 Sedan 29 Sports 19 P1=proportion who prefer a SUV P2=proportion who prefer a truck p3=proportion who prefer a sedan P4=proportion who prefer a sports car Assumptions: Random Samples & all cell counts are at least 5. Use a Chi-Square goodness of fit Test P-val = xcdf(2.24,∞, 3)=0.52

A researcher believes that the number of homicides crimes in CA by season is uniformly distributed. To test this claim, you randomly select 1200 homicides from a recent year and record the season when each happened. Season Freq Spring 312 Summer 299 Fall 297 Winter 293

Results from a previous survey asking people who go to movies at least once a month are shown in the table below. To determine whether this distribution is still the same, you randomly select 1000 people who go to movies at least once a month and record the age of each. Are the distributions the same? Age Survey Freq 2 - 17 26.70% 240 18 - 24 19.80% 214 25 - 39 19.70% 183 40 - 49 14% 156 50+ 207

Homework Worksheet