Hold on tight for Chapter 8. It has confidence intervals which are so important and the major concept of inferential statistics. In a confidence interval, you will predict where the population mean will be within a specific range with a certain percentage of confidence.

In addition to confidence intervals we will also learn what to do when we don't have the population standard deviation, sigma. (We use s and use something called a t-distribution.). This will be very similar to what we do for z, only when we don't have the population standard deviation, we use t.

Finally we will learn another new type of "test", called p. p-test is what we will use to measure and use proportions. It will look very similar to z-tests, but the different will be we will be given a percentage or ration and have to calculate the mean and standard deviation using our proportion formulas. Once we have the mean and standard deviation, we will use the z confidence level formula just like with means.

Good luck and this Chapter will require A LOT of practice!