# MDM4U Bias, quartiles, percentiles, z-scores

We did a lot of stuff today. Here are some notes about bias:

Then we learned about quartiles and percentiles. They’re very similar to median, which divides your data set into two equal parts, except they divide your data set into four parts (quartiles) and 100 parts (percentiles).

We then started into z-scores. Take a look at this short video for a couple of examples. Note that we used sample variables $\bar{x}$ and $s$ today instead of the population versions $\mu$ and $\sigma$.

Homework was page 153 #19.