What’s So Funny About Correlation? xkcd.com. What is Correlation? When two things go together: cookies & milk macaroni & cheese peanut butter & jelly.

Slides:

Advertisements

Similar presentations

A Brief Introduction to Spatial Regression

Advertisements

Co-variation or co-relation between two variables These variables change together Usually scale (interval or ratio) variables.

What’s So Funny About Correlation? Cartoon from xkcd.com.

Relationship between Variables Assessment Statement Explain that the existence of a correlation does not establish that there is a causal relationship.

A recent newspaper article reported that the number of personal computers being sold is increasing. In addition, the number of athletic shoes being sold.

Correlation and Linear Regression

Correlation CJ 526 Statistical Analysis in Criminal Justice.

Describing the Relation Between Two Variables

CJ 526 Statistical Analysis in Criminal Justice

Correlations. Review of Analyses n Chi-Squared –2 Qualitative Variables –Research Question: Are these variables related (Are the frequencies even) –Questions.

Statistical Relationship Between Quantitative Variables

Correlation A correlation exists between two variables when one of them is related to the other in some way. A scatterplot is a graph in which the paired.

Correlational Methods and Statistics. Correlation  Nonexperimental method that describes a relationship between two variables.  Allow us to make predictions.

Describing Relationships: Scatterplots and Correlation

Lecture 17: Correlations – Describing Relationships Between Two Variables 2011, 11, 22.

Correlation and Regression. Relationships between variables Example: Suppose that you notice that the more you study for an exam, the better your score.

Aim: How do we calculate and interpret correlation coefficients with SPSS? SPSS Assignment Due Friday 2/12/10.

Correlation and regression 1: Correlation Coefficient

Chapter 14 – Correlation and Simple Regression Math 22 Introductory Statistics.

Language for describing correlations Do the data points have a pattern that suggests there is correlation? Can a line of best fit be drawn to show the.

Scatterplots October 14, Warm-Up Given the following domain and range in set notation, write the equivalent domain and range in algebraic notation.

Run the colour experiment where kids write red, green, yellow …first.

MEASURES of CORRELATION. CORRELATION basically the test of measurement. Means that two variables tend to vary together The presence of one indicates the.

WHS AP Psychology Research Methods: Correlation. I CAN ANSWER How do psychologists use the scientific method to study behavior and mental processes? What.

Example 1: page 161 #5 Example 2: page 160 #1 Explanatory Variable - Response Variable - independent variable dependent variable.

 Graph of a set of data points  Used to evaluate the correlation between two variables.

Tables and graphs taken from Glencoe, Advanced Mathematical Concepts.

STA291 Statistical Methods Lecture 10. Measuring something over time… o Like a company’s stock value: o It kind of just sits there, making your eyes glaze.

Topic 10 - Linear Regression Least squares principle - pages 301 – – 309 Hypothesis tests/confidence intervals/prediction intervals for regression.

Chapter 4 Describing the Relation Between Two Variables 4.1 Scatter Diagrams; Correlation.

Regression MBA/510 Week 5. Objectives Describe the use of correlation in making business decisions Apply linear regression and correlation analysis. Interpret.

EXPERIMENT VS. CORRELATIONAL STUDY. EXPERIMENT Researcher controls all conditions Experimental group – 1 or more groups of subjects Control group – controlled.

Relationships Scatterplots and correlation BPS chapter 4 © 2006 W.H. Freeman and Company.

3.3 Correlation: The Strength of a Linear Trend Estimating the Correlation Measure strength of a linear trend using: r (between -1 to 1) Positive, Negative.

Correlation iNZight gives r. POSITIVE linear correlation r=1 "Perfect" 0.9

Chapter 4 Summary Scatter diagrams of data pairs (x, y) are useful in helping us determine visually if there is any relation between x and y values and,

Correlation and Regression: The Need to Knows Correlation is a statistical technique: tells you if scores on variable X are related to scores on variable.

5.4 Line of Best Fit Given the following scatter plots, draw in your line of best fit and classify the type of relationship: Strong Positive Linear Strong.

Section 5.1: Correlation. Correlation Coefficient A quantitative assessment of the strength of a relationship between the x and y values in a set of (x,y)

Unit 4 Lesson 2 (5.2) Summarizing Bivariate Data 5.2: Correlation.

MGT-491 QUANTITATIVE ANALYSIS AND RESEARCH FOR MANAGEMENT OSMAN BIN SAIF Session 22.

Chapter 15 Cousins or Just Good Friends? Testing Relationships Using the Correlation Coefficient Part IV Significantly Different: Using Inferential Statistics.

2.5 Using Linear Models A scatter plot is a graph that relates two sets of data by plotting the data as ordered pairs. You can use a scatter plot to determine.

Chapter 4 Scatterplots and Correlation. Chapter outline Explanatory and response variables Displaying relationships: Scatterplots Interpreting scatterplots.

Correlations AP Psychology. Correlations  Co-relation  It describes the relationship b/w two variables.  Example #1  How is studying related to grades?

Relationship between Variables Assessment Statement Explain that the existence of a correlation does not establish that there is a causal relationship.

CHS AP Psychology Unit 1: Science of Psychology Essential Task 1-6:Describe a correlational research study taking into account correlational coefficient,

.  Relationship between two sets of data  The word Correlation is made of Co- (meaning "together"), and Relation  Correlation is Positive when the.

Copyright © 2013, 2010 and 2007 Pearson Education, Inc. Chapter Describing the Relation between Two Variables 4.

ContentDetail  Two variable statistics involves discovering if two variables are related or linked to each other in some way. e.g. - Does IQ determine.

Non-experimental Correlational research u Determine whether 2 or more variables are associated, u If so, to establish direction and strength of relationships.

Prediction and Causation How do we predict a response? Explanatory Variables can be used to predict a response: 1. Prediction is based on fitting a line.

Psychology Research Methods. Characteristics of Good Psychological Research © 2002 John Wiley & Sons, Inc.

Today we will discuss on - Scientific Method Scientific method is the systematic study through prearranged steps that ensures utmost objectivity and.

Correlation & Linear Regression Using a TI-Nspire.

1 Press Ctrl-A ©G Dear 2009 – Not to be sold/Free to use CorrelationCoefficient Stage 6 - Year 11 General Mathematics HSC.

Scatter Plots and Correlation Coefficients

2.7 The Question of Causation

PSYCH - Unit Correlations

REGRESSION (R2).

Review for Test Chapters 1 & 2:

Chapter 14: Correlation and Regression

AGENDA: Quiz # minutes Begin notes Section 3.1.

EQ: How well does the line fit the data?

Bivariate Association: Introduction and Basic Concepts

Investigation 4 Students will be able to identify correlations in data and calculate and interpret standard deviation.

Correlation and Causality

Correlation & Trend Lines

Presentation transcript:

What’s So Funny About Correlation? xkcd.com

What is Correlation? When two things go together: cookies & milk macaroni & cheese peanut butter & jelly

What is Statistical Correlation? A mutual relationship between two variable quantities. Correlation coefficients measure how closely related the two variables are. Stronger relationships mean that a change in one variable is accompanied by a systematic change in the other. Correlation CoefficientStrength 1Perfect Positive 0.7 to 0.9Strong Positive 0.4 to 0.6Moderate Positive 0.1 to 0.3Weak Positive 0No Correlation -0.1 to -0.3Weak Negative -0.4 to -0.6Moderate Negative -0.7 to -0.9Strong Negative Perfect Negative

Does the amount of uranium stored at nuclear plants correlate with the amount of power they generate?

YearUraniumPower

Does the amount of uranium stored at nuclear plants correlate with the amount of power they generate?

Does the amount of uranium stored at nuclear plants correlate with the amount of power they generate?

Why might the amount of uranium stored at nuclear plants correlate with the amount of power they generate?

What is Causation? The action of causing something; the relationship between cause and effect. Smoking causes cancer Sugar causes cavities Gravity causes objects to fall

What is Causation? We can make an inference about a causal relationship based on the strength of correlation. We have to be careful about assuming an actual causal relationship, though.

How does consumption of chicken correlate with crude oil imports?

How does consumption of chicken correlate with crude oil imports? YearPer capita chicken consumption (lbs.) Total crude oil imports (millions of barrels) Chicken data from USDA. Oil data from Dept. of Energy.

How does consumption of chicken correlate with crude oil imports? 0.9

How does consumption of chicken correlate with crude oil imports?

Does eating more chicken cause crude oil imports to increase? ?

But wait… …if eating more chicken doesn’t cause crude oil imports to increase, then why are they so closely correlated? ?

The Lurking Variable Total US Population Year

Correlation and Causation Correlation is a measure of how well data fit a relationship. A correlated relationship between two quantitative variables is not the same as a causal relationship. Causal inferences about correlated events can be made based on underlying theories and knowledge. The determination that one thing causes another requires a scientific experiment.

"Correlation is not causation, but it sure is a hint.“ Edward Tufte, American Statistician

What’s So Funny About Correlation? Cartoon from xkcd.com