Five Variable Situations

Jong Ham

What is your Favorite Color?

• Red• Orange • Yellow• Green• Blue• Sky Blue• Purple• Other

“America’s favorite color reflects a love of true blue”

• Our class size is too small to even get a glimpse of what the favorite color is, but American’s favorite color is blue.

• Color is clearly a categorical variable.• Most often, a case of simple opinion survey

such as “favorite color” involves “C.”

“Middle-age suicide rate up: report”

What variable situation?

• C, Q, Q->Q, C->Q, or C->C

The answer is C->C

• Gender is clearly categorical because one is male or female, and although there are only a few of them compared to the rest of the population, both, and there are even less number of people who fit into this category, neither.

• Time seems to be quantitative, but in this case, the comparison is being made from past to present. Therefore, it is categorical.

• As for death, one is either dead or not, so it is categorical as well.

There are two explanatory variables and one response for this article.

• What are they?

They are…

• Explanatory variable: Time and gender. The title, which states the suicide rate is “up,” gives the clue that the time is the explanatory variable. Gender is also one of them because the article differentiates people who suicide by gender.

• The response is, as the article is about suicide, death.

Texas SAT scores up in math and reading, below national average

What variable situation is this???????

The Answer

• C->Q is the answer.• Again, there are two explanatory variables

and one response. Can you identify them?

The Answer

• As for the first categorical variable, it is time again, which is hinted by the fact that article is making a comparison between the past and present.

• As for the second categorical variable, it is the type of test, which are verbal or math.

• The response is the scores, which is quantitative, unless the article had categorized the scores into under 500, between 501-550, between 551-600, between 601, 650 and so on.

SAT measures more than student performance, research shows it is also

a reliable measure of IQ

Again, what variable situation is this?

The answer is

• Q->Q

• What is interesting about this study is that this can work both ways. If the student’s SAT score is high, it could be a reliable measure of IQ, but if the student’s IQ is high, it could also be a reliable measure of SAT score

Clearly…

• The scores of IQ tests and SAT are quantitative variables.

• Do you know how they could become categorical variables?

That’s right

• Group the IQ scores as, “below 80”, “between 81-85,” “ between 86-90,” “between 91-95” and so on. The sat scores can be grouped in a similar way as well.

“Census shows a modest rise in U.S. Income

Again, what is the variable situation?

The Answer is Q

• Q• The time, which is an explanatory variable in

this case, is quantitative in nature

Thanks

• Very Much• If you want more information about five

variable situations, you can certainly• -google them• -ask questions about it• -or even form a club!