How To - Variance & Standard Deviation

Hey Guys, today we do a quick intro on some basic terms and formulas that are used frequently in statistics

- Mode or Modal Value, Middle Value, Median, Variance and the Standard Deviation

We have a class of 8 Girls and 8 Boys, so a total of 16 kids. To get the Modal Value (m) and therefore represent the level of the whole class, we count how often each grade showed up - in our case 2 and 3

Next comes what probably everyone did at least once in school; calculate the class average or our Middle Value (a small X with a line over its top; sorry I can't write it out here .__. )

Using the Median is actually just being nit-picky, but good to know. In case your teacher breaks into your house in the middle of the night and wants to know... you will probably never use this one in your life
For uneven: look for the middle number
For even: look for the two middle numbers, sum them up and divide by 2 - that's your median

The formula for Variance may look difficult at first, but you just subtract the middle value from your first grade, square that shit and carry on like this for the rest of the grades; then you add them all up and divide the sum by the total number of grades or kids - there you go.

Here, last but not least - the very simple formula for Standard Deviation, the average deviation for students and how their grades differ from the middle value.

And that's it ^-^

I make these tutorials with the goal of making knowledge accessible in the least possible amount of time.
Each of my posts usually take 30-60min to produce, but reading and understanding them is usually done
in 5-10min.
If you have any trouble or suggestions, please... be suggestive ^^ (ha ha ha. pun intended)


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