The liberals here periodically post graphs, allegedly supporting whatever it is they say. It is practically a rule that they misinterpret those graphs. Or that the graphs are skewed to be misleading by whatever liberal organ churned them out.
So as a public service I will explain how to read a graph or chart.
First look at the X and Y axes and see what it is they purport to measure. Be very careful of terms. "Average income" is not "average household income" is not "wages". Those are at least 3 separate concepts.
While we're there, know that "average" can mean any of three things:
1) Mean. This is what people typically think of as average. You have 4 people. 1 earns $20,000 a year, the other 3 earn 100,000 a year. The average (mean) is 320,000/4=80,000.
2) Median. The midpoint between the high and low. The low in our example is 20k and the high is 100k so the average (median) is $60k.
3) Mode. The most commonly occuring element. In our example the average (mode) is 100k.
So it is fair to say that 80k, 60k and 100k are all the "average" for the example I gave. All of them are true but someone can mislead by using different defintiions.
Next, look at whatever trend the graph shows. Are there multiple explanations for whatever it is? If the graph meaures household whatever, remember that households have gotten smaller over the years, with many more single heads of households. So let's look at that.
There are two couples. Smith earns $75000/yr as an account and Mrs SMith earns 40k as a preschool teacher. Jones make $50k as a truck driver. Mrs Jones makes 100k as a pediatrician. So the household average income is $132,500
Now they both get divorced. After the divorce the average household income is 66,250. Holy cow! Household income is down! Blame George Bush. But it has nothing to do with that.
Similarly people enter the workforce, people leave the workforce, information isnt reported, some periods are atypical for one reason or another. But it bears asking critical questions when confronted with a graph, no matter what the source.
So as a public service I will explain how to read a graph or chart.
First look at the X and Y axes and see what it is they purport to measure. Be very careful of terms. "Average income" is not "average household income" is not "wages". Those are at least 3 separate concepts.
While we're there, know that "average" can mean any of three things:
1) Mean. This is what people typically think of as average. You have 4 people. 1 earns $20,000 a year, the other 3 earn 100,000 a year. The average (mean) is 320,000/4=80,000.
2) Median. The midpoint between the high and low. The low in our example is 20k and the high is 100k so the average (median) is $60k.
3) Mode. The most commonly occuring element. In our example the average (mode) is 100k.
So it is fair to say that 80k, 60k and 100k are all the "average" for the example I gave. All of them are true but someone can mislead by using different defintiions.
Next, look at whatever trend the graph shows. Are there multiple explanations for whatever it is? If the graph meaures household whatever, remember that households have gotten smaller over the years, with many more single heads of households. So let's look at that.
There are two couples. Smith earns $75000/yr as an account and Mrs SMith earns 40k as a preschool teacher. Jones make $50k as a truck driver. Mrs Jones makes 100k as a pediatrician. So the household average income is $132,500
Now they both get divorced. After the divorce the average household income is 66,250. Holy cow! Household income is down! Blame George Bush. But it has nothing to do with that.
Similarly people enter the workforce, people leave the workforce, information isnt reported, some periods are atypical for one reason or another. But it bears asking critical questions when confronted with a graph, no matter what the source.
