The incomplete table and histogram give information about the waiting time, in minutes, experienced by patients at a dental surgery.

\begin{tabular}{|c|c|}
\hline Time ([tex]$t$[/tex] minutes) & Frequency \\
\hline [tex]$0\ \textless \ t\ \textless \ 30$[/tex] & 15 \\
\hline [tex]$30\ \textless \ t\ \textless \ 40$[/tex] & 35 \\
\hline [tex]$40\ \textless \ t\ \textless \ 60$[/tex] & 50 \\
\hline [tex]$60 \leq t\ \textless \ 80$[/tex] & 20 \\
\hline [tex]$80\ \textless \ t\ \textless \ 100$[/tex] & 10 \\
\hline
\end{tabular}

a) Use the histogram to complete the table.

b) Use the table to complete the histogram.



Answer :

Certainly! Let's work through the steps to complete both the table and the histogram.

### Part (a) Completing the Table

From the provided data, we have the waiting times and their corresponding frequencies:

1. Interval [tex]\( 0 < t < 30 \)[/tex]: The frequency is 15.
2. Interval [tex]\( 30 < t < 40 \)[/tex]: The frequency is 35.
3. Interval [tex]\( 40 < t < 60 \)[/tex]: The frequency is 50.
4. Interval [tex]\( 60 \leq t < 80 \)[/tex]: The frequency is 20.
5. Interval [tex]\( 80 < t < 100 \)[/tex]: The frequency is 10.

These values are already listed, so we can confirm the table is complete as provided:

[tex]\[ \begin{array}{|c|c|} \hline \text{Time} \; ( t \; \text{minutes}) & \text{Frequency} \\ \hline 0 < t < 30 & 15 \\ \hline 30 < t < 40 & 35 \\ \hline 40 < t < 60 & 50 \\ \hline 60 \leqslant t < 80 & 20 \\ \hline 80 < t < 100 & 10 \\ \hline \end{array} \][/tex]

### Part (b) Completing the Histogram

To complete the histogram, we need to plot the frequencies for each time interval on a graph. Here’s a step-by-step guide:

1. Label the X-axis and Y-axis:
- X-axis: Represents the time intervals in minutes.
- Y-axis: Represents the frequency of patients.

2. Mark the intervals on the X-axis:
- Divide the X-axis into the given time intervals: [tex]\( 0 < t < 30 \)[/tex], [tex]\( 30 < t < 40 \)[/tex], [tex]\( 40 < t < 60 \)[/tex], [tex]\( 60 \leq t < 80 \)[/tex], and [tex]\( 80 < t < 100 \)[/tex].

3. Plot the frequencies as bars for each interval:
- For [tex]\( 0 < t < 30 \)[/tex], draw a bar up to the frequency of 15.
- For [tex]\( 30 < t < 40 \)[/tex], draw a bar up to the frequency of 35.
- For [tex]\( 40 < t < 60 \)[/tex], draw a bar up to the frequency of 50.
- For [tex]\( 60 \leq t < 80 \)[/tex], draw a bar up to the frequency of 20.
- For [tex]\( 80 < t < 100 \)[/tex], draw a bar up to the frequency of 10.

4. Ensure the heights of the bars correspond to the frequencies:
- Bar height for [tex]\( 0 < t < 30 \)[/tex] should be 15.
- Bar height for [tex]\( 30 < t < 40 \)[/tex] should be 35.
- Bar height for [tex]\( 40 < t < 60 \)[/tex] should be 50.
- Bar height for [tex]\( 60 \leq t < 80 \)[/tex] should be 20.
- Bar height for [tex]\( 80 < t < 100 \)[/tex] should be 10.

Ensure to use an appropriate scale on the Y-axis so that all frequencies fit well within the graph.

### Summary

- The table of waiting times and their frequencies is already complete.
- To complete the histogram, plot the intervals on the X-axis and draw bars with heights corresponding to the frequencies on the Y-axis.

This completes parts (a) and (b) effectively.

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