## Z-Scores (4)

This is the standard type of table you will see in most Statistics Textbooks.

If you are allowed to use a calculator for calculating Z-scores and areas under the curve, I suggest you glance at this to get familiar with what it is, and MOVE ON.

**If you are NOT allowed to use a calculator, it would be a good idea to get friendly with this table - and FAST. During an exam, the last thing you want to be worrying about is figuring out how to find your way around this thing!**

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?

**Sometimes we need a standardized scale to measure a value's distance from the center. **

**A Z-score indicates how many STANDARD DEVIATIONS a value is from the mean. **

**The official formula is:**

**So let's say the MEAN is 100 and the Standard Deviation is 15. **

**If you are given a value of 132, you just plug that into the formula above. **

**132 - 100 = 32**

**32 / 15 = 2.133 **

**VOILA - Your Z-Score is 2.133**

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: