Critical Thinking Questions -Why Should a Poll Be Scientific Rather Than Informal

Critical Thinking Questions
$\begin{array}{|l|l|l|l|l|}\hline \text { RATING } &\text { Failing }&\text { Below Average } &\text { Competent }&\text { Advanced/ }\\&&&&\text { Sophisticated }\\\hline \text { Criteria } &\text { Answer doesnot }&\text { Answer fails to }&\text { Answer provides }&\text { Answer clearly }\\\text { for }&\text { provide an }&\text { provide examples }& \text { an argument with } &\text { provide an }\\\text { evaluation. }&\text { argument for or }&\text { to support an }&\text { one or two }&\text { argument with two }\\&\begin{array}{l}\text { against. Answer } \\\text { contains }\end{array} & \begin{array}{l}\text { argument for or } \\\text { against. Writing }\end{array} & \begin{array}{l}\text { examples that } \\\text { support it. Writing }\end{array} & \begin{array}{l}\text { excellent } \\\text { examples that }\end{array}\\&\text { inaccuracies. } & \text { is poor and } & \text { is acceptable for }& \text { support it; student } \\&\text { Writing is poor } &\text { grammatical }& \text { the college level } &\text { makes the argument }\\&\text { and contains } & \text { errors are } & \text { but may contain } &\text { clearly and }\\&\text { numerous } & \text { common. Answer } & \text { one or two }&\text { eloquently. Answer }\\&\begin{array}{l}\text { grammatical } \\\text { mistakes and }\end{array} & \begin{array}{l}\text { is somewhat } \\\text { incoherent. }\end{array} &\begin{array}{l}\text { grammatical } \\\text { mistakes and }\end{array} & \begin{array}{l}\text { is well organized } \\\text { and free of }\end{array}\\&\text { misspellings. }&&\text { misspellings. }&\text { grammatical errors }\\&&&&\text { and misspellings. }\\\hline \text { POINT } \\\text { VALUE }&0&1&2&3\\\hline\end{array}$

-Why should a poll be scientific rather than informal?