Biostats Linear Regression Flashcards
Is the next step up after correlation. It is used when we want to predict the value of a variable based on the
value of another variable
Linear Regression
The variable we want to predict is
called the dependent variable (or sometimes called as the ________________)
Outcome variable
The variable we are using to predict the other variable’s value is called the independent variable, referred to as
Predictor variable
We could use _________________ to understand whether exam
performance can be predicted based on revision time; whether cigarette consumption can be predicted based on smoking duration; and so forth.
linear regression
If you have two or more independent
variables, rather than just one, you need to use
Multiple regression.
Is closely related to correlation
Linear Regression
focuses on using the relationship for prediction
Regression
If the relationship is perfect, the prediction is also
perfect
The vertical difference between the
data points and the predicted
regression line is known as the
Residuals
These values are squared to remove the negative numbers and then summed to give
SSR
The vertical difference between the
data points and the mean of the
outcome variable can be calculated.
These values are squared to remove
the negative numbers and then
summed to give the total sum of the
squares
SST (shows how good the mean value is as a model of the outcome scores.)
The vertical difference between the
mean of the outcome variable and the
predicted regression line is now
determined. Again these values are
squared to remove the negative
numbers and then summed to give
model sum of squares (SSM) - how better the model is compared to just using the mean of the outcome variable.
how better the model is compared to just using the mean of the outcome variable.
SSM
Total sum of the squares
SST
the larger the SSM the better the model is at predicting the _______ compared to the ________________. If this is accompanied by a _________ the model also has a small error
outcome, mean value alone, small SSR