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Statistical Questions

A statistical question is one for which you don't look to get a single respond. Instead, you expect to get a variety of different answers, and you are interested in the distribution and trend of those answers.

For instance, "How tall are you?" is not a statistical question. Just "How tall are the students in your school?" is a statistical question.

Central Tendency

When the answers to a statistical question are numerical data, nosotros tin can ask about the central tendency of that data. For example, we might want to know, roughly, "how alpine are most people in your school?"

However, this is non a precise question. There are ways of measuring of central tendency using a single number: you tin can detect the mean (or boilerplate), the median, or the fashion of the data.

Variation

Suppose you know that the average elevation of a student in a school is v feet. You lot may nevertheless be interested in the spread of the information. Is anybody nearly 5 feet tall, say inside 2 inches? Or are there also very brusk and very tall people in the school?

The simplest mensurate of the variation is the range , calculated by subtracting the lowest value from the highest. More complex measures of variation include the interquartile range and the standard deviation or variance .

Beneath is a graph of two data sets, showing the number of students in 2 schools that got a particular score on a x -problem quiz.

Both data sets have the same range ( 10 ), the same hateful (a little more than half-dozen ), and the same total number of students (you can't tell this hands from the graph, but it's true.) Nonetheless, the heights of the blue blocks vary considerably compared to that of cherry blocks.