Let's fill in the missing values step-by-step, considering the provided answer to ensure accuracy.
First, observe the data given:
- For 8th grade: 20 students spent more than an hour, and 30 students spent less than an hour.
- Total students surveyed: 77.
- Total students who spent more than an hour: 33.
- Total students across all categories: [tex]\(7 + 70 - 7 = 77\)[/tex] (since the total in the table should sum up to 77, even though it is differently formatted).
Now, we'll deduce the missing values:
1. Total number of 8th grade students:
- The sum of 8th grade students who spent more and less than an hour is [tex]\(20 + 30 = 50\)[/tex].
- So, the total number of 8th grade students is 50.
Filling in the table:
[tex]\[
\begin{tabular}{|c|c|c|c|}
\hline & More & Less & Total \\
\hline 7th grade & $\square$ & $\square$ & $\square$ \\
\hline 8th grade & 20 & 30 & 50 \\
\hline Total & 33 & & 77 \\
\hline
\end{tabular}
\][/tex]
2. Total number of 7th grade students:
- Since the grand total of students surveyed is 77 and the total number of 8th grade students is 50, then the number of 7th grade students is [tex]\(77 - 50 = 27\)[/tex].
Filling in the table:
[tex]\[
\begin{tabular}{|c|c|c|c|}
\hline & More & Less & Total \\
\hline 7th grade & $\square$ & $\square$ & 27 \\
\hline 8th grade & 20 & 30 & 50 \\
\hline Total & 33 & & 77 \\
\hline
\end{tabular}
\][/tex]
3. Number of 7th grade students who spent more than an hour:
- Total students who spent more than an hour is 33.
- 8th grade students who spent more than an hour is 20.
- Therefore, the number of 7th grade students who spent more than an hour is [tex]\(33 - 20 = 13\)[/tex].
Filling in the table:
[tex]\[
\begin{tabular}{|c|c|c|c|}
\hline & More & Less & Total \\
\hline 7th grade & 13 & $\square$ & 27 \\
\hline 8th grade & 20 & 30 & 50 \\
\hline Total & 33 & & 77 \\
\hline
\end{tabular}
\][/tex]
4. Number of 7th grade students who spent less than an hour:
- Total number of 7th grade students is 27.
- Number of 7th grade students who spent more than an hour is 13.
- Therefore, the number of 7th grade students who spent less than an hour is [tex]\(27 - 13 = 14\)[/tex].
Filling in the table:
[tex]\[
\begin{tabular}{|c|c|c|c|}
\hline & More & Less & Total \\
\hline 7th grade & 13 & 14 & 27 \\
\hline 8th grade & 20 & 30 & 50 \\
\hline Total & 33 & 44 & 77 \\
\hline
\end{tabular}
\][/tex]
By following these steps, all the missing values in the table are accurately filled.
