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riosjosh

If we were only interested in the sample then we wouldn’t need statistics. We want to generalize and know the significance.

Is it weird enough?
Is it significant?

Normal distribution – don’t violate this when using statistics

The sample is your data. Population is the “real world”.

Averages
Mean – the sum divided by the number of occurrences

Median – the middle point
Mode – the most frequent occurrence

N = number in population
n = number in sample

Greek letters are used in the population whereas regular letters are used in the sample.

Quantify the dispersion this is the first step.

X(bar) = Sum Xs/N

The magical 3-step journey
1) Variation = SUM X^2 - (SUM X)^2/N
2) Variance = Average Dispersion = SS/N = S^2 = d^2
3) Standard Deviation use the square root

The quantification of dispersion is the question that you really want to ask.

Make your homework neat. Put a cover page on your homework.

## COMM3710 - Fall 2011 - Section 001 - Lecture Notes - 09/01

*Please enter 3 lines between the last entry and put in your username using heading 3 then type in your notes.*## *Note on this and probably subsequent notes, some symbols such as the SUM symbol are not recognized by this wiki. Make sure that you look through your notes and change the symbols.*

## riosjosh

If we were only interested in the sample then we wouldn’t need statistics. We want to generalize and know the significance.Is it weird enough?

Is it significant?

Normal distribution – don’t violate this when using statistics

The sample is your data. Population is the “real world”.

Averages

Mean – the sum divided by the number of occurrences

Median – the middle point

Mode – the most frequent occurrence

N = number in population

n = number in sample

Greek letters are used in the population whereas regular letters are used in the sample.

Quantify the dispersion this is the first step.

X(bar) = Sum Xs/N

The magical 3-step journey

1) Variation = SUM X^2 - (SUM X)^2/N

2) Variance = Average Dispersion = SS/N = S^2 = d^2

3) Standard Deviation use the square root

The quantification of dispersion is the question that you really want to ask.

Make your homework neat. Put a cover page on your homework.