Introduction to Statistics: Difference between revisions

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== Random Variables ==
== Random Variables ==


It's usually possible to represent the outcome of experiments in terms of a representation involving integers or real numbers.  For instance, in the case of flipping a coin, it becomes a little cumbersome to record the outcomes of multiple experiments.  Let's say we flip a coin four times, and repeat this experiment twice.  We might have gotten the following outcomes from the two experiments.<br>
It's usually possible to represent the outcome of experiments in terms of integers or real numbers.  For instance, in the case of flipping a coin, it becomes a little cumbersome to record the outcomes of multiple experiments.  Let's say we poll ten people for their voting preferences (Republican - R, or Democrat - D) in two different electorial districts.  Our results might look like this:<br>
<math>\{HHTH\}</math> and <math>\{TTHH\}</math><br>
<math>\{RRRDRRDRRR\}</math> and <math>\{DDDDDRDDDD\}</math><br>
But if we're only really interested in the number of times that the coin turns up heads in four flips, we can assign an integer value of 0 to Tails and 1 to Heads.  Adding the the values together for each experiment gives us what we were after in the first place.
But we're probably only interested in the overall breakdown in voting preference for each district.  If we assign an integer value to each outcome, say 0 for Democrat and 1 for Republican, we can obtain a concise summary of the voting preference district by district by adding the results together.