The IQ scores of 50 students are given below.

\begin{tabular}{|r|r|r|r|r|r|r|r|r|r|}
\hline
96 & 100 & 86 & 117 & 89 & 86 & 117 & 107 & 100 & 115 \\
\hline
112 & 111 & 117 & 98 & 117 & 101 & 87 & 113 & 92 & 92 \\
\hline
96 & 101 & 87 & 109 & 103 & 116 & 91 & 101 & 103 & 89 \\
\hline
101 & 104 & 111 & 90 & 113 & 87 & 89 & 116 & 104 & 112 \\
\hline
96 & 110 & 104 & 106 & 118 & 97 & 117 & 100 & 118 & 87 \\
\hline
\end{tabular}

(a) Construct a grouped frequency distribution for the data. Use [tex]$85-89$[/tex] for the first class and use the same width for each subsequent class.

\begin{tabular}{|c|c|}
\hline
Class & Frequency \\
\hline
[tex]$85-89$[/tex] & \\
\hline
[tex]$90-94$[/tex] & \\
\hline
[tex]$95-99$[/tex] & \\
\hline
[tex]$100-104$[/tex] & \\
\hline
[tex]$105-109$[/tex] & \\
\hline
[tex]$110-114$[/tex] & \\
\hline
[tex]$115-119$[/tex] & \\
\hline
\end{tabular}



Answer :

Sure, let's construct a grouped frequency distribution for the given IQ scores with class intervals starting at [tex]\(85-89\)[/tex] and subsequent intervals having the same width.

First, identify the class intervals:
1. [tex]\(85-89\)[/tex]
2. [tex]\(90-94\)[/tex]
3. [tex]\(95-99\)[/tex]
4. [tex]\(100-104\)[/tex]
5. [tex]\(105-109\)[/tex]
6. [tex]\(110-114\)[/tex]
7. [tex]\(115-119\)[/tex]

Next, determine the frequency (number of occurrences) of IQ scores within each class interval.

- For the interval [tex]\(85-89\)[/tex]: [tex]\( \{86, 86, 89, 87, 87, 89, 87, 89, 87 \} \rightarrow 9\)[/tex]
- For the interval [tex]\(90-94\)[/tex]: [tex]\( \{92, 92, 91, 90 \} \rightarrow 4\)[/tex]
- For the interval [tex]\(95-99\)[/tex]: [tex]\( \{96, 98, 96, 96, 97 \} \rightarrow 5\)[/tex]
- For the interval [tex]\(100-104\)[/tex]: [tex]\( \{100, 100, 101, 103, 101, 101, 103, 101, 104, 104, 100, 101 \} \rightarrow 12\)[/tex]
- For the interval [tex]\(105-109\)[/tex]: [tex]\( \{107, 109, 106 \} \rightarrow 3\)[/tex]
- For the interval [tex]\(110-114\)[/tex]: [tex]\( \{112, 111, 113, 111, 113, 112, 110 \} \rightarrow 7\)[/tex]
- For the interval [tex]\(115-119\)[/tex]: [tex]\( \{117, 117, 117, 117, 116, 116, 118, 117, 118, 115 \} \rightarrow 10\)[/tex]

Constructing the frequency distribution table, we have:

[tex]\[ \begin{tabular}{|c|c|} \hline Class Interval & Frequency \\ \hline 85-89 & 9 \\ \hline 90-94 & 4 \\ \hline 95-99 & 5 \\ \hline 100-104 & 12 \\ \hline 105-109 & 3 \\ \hline 110-114 & 7 \\ \hline 115-119 & 10 \\ \hline \end{tabular} \][/tex]

Thus, the grouped frequency distribution for the given IQ scores is:

[tex]\[ \begin{array}{|c|c|c|} \hline Class Interval & Frequency \\ \hline 85-89 & 9 \\ \hline 90-94 & 4 \\ \hline 95-99 & 5 \\ \hline 100-104 & 12 \\ \hline 105-109 & 3 \\ \hline 110-114 & 7 \\ \hline 115-119 & 10 \\ \hline \end{array} \][/tex]

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