00:01
Okay, so suppose i want to calculate the average household income.
00:06
Well, i have a sample of different incomes and how many people are in different incomes.
00:12
So really what i'm competing is the expected value.
00:16
What is the expected value? well, recall that the expected value is some of all the x values times the probabilities.
00:24
But notice i have a range here of my x value, so like $0 to $19 ,99.
00:31
What would my x value be? well, let's average these.
00:34
Average, just add them up, divide by two.
00:38
This average income would be $9 ,99 .50.
00:42
What about the interval from $20 ,000 to $39 ,99? again, add them divided by two.
00:51
This would be about $29 ,99 .50 and so on and so forth.
00:56
So my different expected values are the averages in each.
01:01
Income 2 ,999 .5.
01:06
Also between 40 and 59 ,499 ,000, add them both, divided by two, between $600 ,79 ,000, $0 .59 ,000, and then finally, between $809 ,99 ,000...