Download presentation

Presentation is loading. Please wait.

1
**Chapter 7: Correlation doesn’t mean causation**

Stats Chapter 7: Correlation doesn’t mean causation

2
Do Now: The following graph shows ages of men and woman who are married to each other. Based on the graph, would calculating the correlation coefficient be appropriate? Why? Why not?

4
**Pirates are causing global warming?**

5
EVIL MAN PIRATE.

6
**Cheese is killing people?**

7
**Margarine killing the love?**

8
**Political Action Committees are killers?**

9
Skiing facilities! NO!!!!

10
Hmmmm…. Do NOT confuse association, correlation and causation.

11
Association Deliberately vague term to describe the relationship between two variables. This can be used for CATEGORICAL data Ex: Did you know there’s a strong correlation between playing an instrument and drinking coffee…. NO. It’s an association!

12
Correlation Precise term describing the strength and direction of the linear relationship between quantitative variables.

13
Causation Scatterplots and correlation coefficients NEVER prove causation. This is why it is so hard to prove something causes something else– for example, just because lung cancer and smoking is correlated doesn’t mean that one causes the other and when considering one causing the other you need to consider both. Does smoking cause cancer? OR Does cancer cause smoking? You need to do further tests to actually figure this out.

14
Example 1 A news reporter claims “There appears to be a strong correlation between whether you own a pet and the condition of a person’s yard.” Thoughts on this?

15
Example 2: A researcher studies children in elementary school and finds a strong positive linear association between height and reading scores. Does this mean that taller readers are generally better readers? What might explain the strong correlation?

16
What is wrong? Example 3 The correlation coefficient between Olympic gold medal times for the 800 m hurdles and year is seconds per year.

17
Answer Correlation Coefficient has NO UNITS.

18
What’s wrong? Example 4 The correlation coefficient between Olympic Gold Medal times for the 100m dash and year is -1.37

19
Answer Correlation Coefficient of is impossible! Correlation coefficient will always be between -1 and 1!

20
What’s Wrong? Example 5 Since the correlation coefficient between Olympic gold medal times for the 800m hurdles and 100m dash is -0.41, the correlation coefficient between times for the 100m dash and the 800m dash hurdles will be 0.41

21
Answer Correlation does not change if we reverse x and y variables.

22
What’s Wrong?- Example 6 If we were to measure Olympic gold medal times for the 800m hurdles in minutes instead of seconds, the correlation coefficient would be -.66/60 =

23
Answer Correlation does not change when we change units!

24
**Practice Problems Try some on your own!**

As always call me over if you are confused!

25
**Exit Ticket Explain the error:**

Your friend claims that the correlation coefficient between what continent you live on and how many hours you sleep is

Similar presentations

OK

Warm Up Read over the Activity at the beginning of Chapter 3 (p. 120) AP Statistics, Section 3.1, Part 1 1.

Warm Up Read over the Activity at the beginning of Chapter 3 (p. 120) AP Statistics, Section 3.1, Part 1 1.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on file system in unix everything is a file Ppt on acute coronary syndrome nursing Ppt on integration problems and solutions Ppt on different types of dance forms of india Simple backgrounds for ppt on social media Ppt on profit planning in banks Animated ppt on magnetism video Ppt on do's and don'ts of group discussion images Presentations ppt online shopping Ppt on median and altitude of a triangle