deletions | additions       diff --git a/chapter 7.tex b/chapter 7.tex  index 906ed46..1786a86 100644  --- a/chapter 7.tex  +++ b/chapter 7.tex 
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Pro pollsters want to ensure the sample they take is representative of the population//  \subsection{Bias}  a method is biased if it has a tendency to produce an untrue value.\\  $\textbf{sampling bias} bias}$  results from taking a sample that is not representative of the population\\ $\textbf{Measurement bias}$ comes from asking questions that do not produce a true answer due to confusing wording or misleading questions\\  In a $\textbf{Voluntary response sample}$ a large group of individuals are invited to respond, those who do are counted.\\  these almost always biased\\