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

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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.