mgf1107lecture33 - MGF 1107 EXPLORATIONS IN MATHEMATICS...

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MGF 1107 – EXPLORATIONS IN MATHEMATICS LECTURE 33 Descriptive Statistics In the previous lecture we looked at how to collect data. Once that task is complete, we have results that need to be interpreted, and so the next challenge is how to describe the data in a way that will allow us to make statistical hypotheses. One natural thing to ask when interpreting the result of a survey is “What is the average value?” since it takes into account all the results and presents an easily understood measure of how the “typical person” responded (even though it may not represent the performance of any single person. For example, while the average on an exam might be 78.3%, it is very possible for no one to have that score.) We will discuss the most common measures of central tendency (usually referred to as averages ) below, starting with the mean, which tends to be inferred when people talk about an average. Arithmetic Mean The arithmetic mean , symbolized by (when calculating the mean of a sample) or μ (when calculating the mean of an entire population), is calculated by adding up the sum of all the data values and dividing by the sample size. If the data values are x 1 , x 2 , …, x n we can write
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Ex. Given the following scores from an exam, find the class mean. Median
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mgf1107lecture33 - MGF 1107 EXPLORATIONS IN MATHEMATICS...

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