## Mandy's Notes

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Disclaimer: I did not create nor do I own these videos. I have simply embedded them, courtesy of YouTube.

This is a great video because it gives walk-throughs of z-score calculations from homework problems. You may not have these exact problems, but the same concepts can be applied to your own work!

These examples rely on the Z-Score Formula:

MEMORIZE this formula, make sure you know it COLD!

If you do not know what the "m-like" symbol or the "o" with a tail are, check out What's with the Greek?

The SAMPLE MEAN is the mean of a sample.

The POPULATION MEAN is the mean of the population.

Different symbols make the distinction between these two, although the formulas are exactly the same.

**The ONLY difference between the two is that the SAMPLE MEAN is referred to as "x bar" whereas the POPULATION MEAN is referred to as "mew." BOTH are found by calculating the SUM of all values you are given and dividing by "N," the number of total values. **

We can often use x bar, the SAMPLE MEAN, to draw conclusions about the mean of the entire population.

Disclaimer: I did not create nor do I own these videos. I have simply embedded them, courtesy of YouTube.

It is very important that you understand what a Z-score represents as well as how to obtain a Z-score manually, by hand.

HOWEVER, you should also know how to get around your TI-83 or 84 series calculator. Use it to find a Z-Score and the AREA under a curve.

And here is another, more comprehensive overview of Z-Scores: