Today we had a double class, and on the morning class we had a quiz, which was composed to two questions exactly as they appeared on last night's homework. It was an easy way for Mr. K. to tell who did their homework and who did not. We then went over all the answers in it and how they are marked, so we have a better idea what can hurt you in a test in the future. Remember,

**SHOW YOUR WORK**

After the quiz we started the new lesson for the day, called

*The Normal Curve*. By definition, the Normal Distribution is a frequency distribution that can be represented by a symmetrical bell-shaped curve which shows that most of the data are concentrated around the centre (or the mean) of the distribution.

Remember, normally, data would never fit in the normal perfectly, but there are many situations where the data is approximately normal.

We also learned that the Normal Curve is related to the standard deviation rule mentioned earlier in the course, the

**68-95-99 rule**, which means that:

Then, for the afternoon class, we were separated into groups and worked on 4 different problems using the normal curve. We had to find out if the data was approximate to the normal distribution or not, and also learned a new way to find it in your calculator... by graphing it!

So, the first way is to find the mean and the standard deviation, by going to 1 variable statistics, or 1-Var Stats, and adding/subtracting the standard deviation to the mean once, twice and three times. Then you turn what you just calculated into percentages, and compare with the 68-95-99 rule. If the percentages are somewhat near 68, 95 and 99, then the data is normal.

The second way, which in my opinion if much easier, is to simply list all the data in your calculator, and graph it by going to stat plot and setting the Xlist to L1 (or whichever list you punched the data in) and the Frequency to 1. Then you would go to zoom and select ZoomStat so the graph fits nicely in your screen.

Well, I guess this about sums it up for what we did today in class, hope my post was of any help. The scribe for tomorrow can be Adamson (bet you wish you didn't give me birthday beats yesterday now haha)

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