Let's Get Brainwashed.

This afternoon we studied hypothesis testing. In some ways it sounds so basic, but the method of getting the answer is rather involved.

For example:

You want to know if something made a change or not. So you have two statements:

There was no change.
There was a change.

You could take a guess, but why do that? Let's make some signal noise for numbers! Conceptually, all hypothesis tests are the same in that a signal (lambda)-to-noise (sigma) ratio is calculated (lambda/sigma) based on the before and after data. This ratio is converted into a probability, called the p-value. So now, calculate the p-value and compare it to the alpha. (The alpha is usually 0.05).

If:

p-value < alpha, go with statement 2 (there was a change).
p-value >= alpha, go with statement 1 (there was no change).

But only do this if your confidence level is 95% or higher.*


*Confidence levels depend upon each situation's set of circumstances. 95% is only a guideline.

Labels: loose marbles