Department

Political Science

Course Code

POL242Y1

Professor

Joseph Fletcher

Tuesday January 11, 2011

Regression equation: y = a + bx

y = the predicted value, or the dependent variable

and x = the independent variable

a = intercept (y when x = 0 )

b = the slope of a line

we're going to discuss this more next week

regression and correlation fit together in a way, since correlation is defined by a regression

equation

people think interval data is more powerful than nominal or ordinal....

bivariate analysis:

if we want to predict y from x the scores from x must be at least as efficient as the scores of y

as the mean of y itself.

So we have two axes and the idea is that there's one independent and one dependent

variable. These variables have ranks that some things are higher than others, and that

there's a constant interval between each of the units. It's measured in some set of units i.e. x

= years of education. Now the idea here is that we can have a number of individual cases

that are ranked on x or ranked on y. the best predictor of y (just y, alone) would be whatever

the mean score of y is. and the reason that it' s the best predictor is that y would give us the

smallest average deviation of the mean of y. so the mean of the sample becomes the standard

of which we compare any other variable.

so the square deviation of the mean score will let us decide if x is useful.

pg. 309 in brians (only just touched upon on that page).

there's more than one kind of variance or variation. in fact there's 3 we need to worry about...

Types of Variation

1) Total Variance

- It equals the sum of the square differences from the mean on any variable

- The average squared deviation = the total variation of the y variable

- "The least squares line"

2) Unexplained Variance

- Everything that's left over (that doesn't touch the regression "slope" aka the

equation

"y = a + bx")

3) Explained Variance

- Total variation of y that can be attributed to the influence of x

- Pearson's correlation = the square root of the variance.

- So r = the square root of explained variance.

www.notesolution.com

Over 90% improved by at least one letter grade.

OneClass has been such a huge help in my studies at UofT especially since I am a transfer student. OneClass is the study buddy I never had before and definitely gives me the extra push to get from a B to an A!

Leah â€” University of Toronto

Balancing social life With academics can be difficult, that is why I'm so glad that OneClass is out there where I can find the top notes for all of my classes. Now I can be the all-star student I want to be.

Saarim â€” University of Michigan

As a college student living on a college budget, I love how easy it is to earn gift cards just by submitting my notes.

Jenna â€” University of Wisconsin

OneClass has allowed me to catch up with my most difficult course! #lifesaver

Anne â€” University of California

Join OneClass

Access over 10 million pages of study

documents for 1.3 million courses.

Sign up

Join to view

OR

By registering, I agree to the
Terms
and
Privacy Policies

Already have an account?
Log in

Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.