Looking for reliable answers? Westonci.ca is the ultimate Q&A platform where experts share their knowledge on various topics. Our platform provides a seamless experience for finding reliable answers from a knowledgeable network of professionals. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform.

Michael recorded the maximum temperature every day in September. The table shows information about his results.

\begin{tabular}{|c|c|}
\hline Temperature [tex]$\left({ }^{\circ} C \right)$[/tex] & Frequency \\
\hline [tex]$14 \ \textless \ t \leqslant 18$[/tex] & 4 \\
\hline [tex]$18 \ \textless \ t \leqslant 20$[/tex] & 10 \\
\hline [tex]$20 \ \textless \ t \leqslant 22$[/tex] & 8 \\
\hline [tex]$22 \ \textless \ t \leqslant 24$[/tex] & 5 \\
\hline [tex]$24 \ \textless \ t \leqslant 28$[/tex] & 3 \\
\hline
\end{tabular}

1. Find the class interval that contains the median.

2. Calculate an estimate for the mean maximum temperature.

Sagot :

Sure! Let's carefully go through the steps to solve the problem.

### Step 1: Organize the Data
The data is already given in a table format:

| Temperature [tex]\( \left({ }^{\circ} C \right) \)[/tex] | Frequency |
|----------------------------------------------|-----------|
| [tex]\(14 < t \leq 18\)[/tex] | 4 |
| [tex]\(18 < t \leq 20\)[/tex] | 10 |
| [tex]\(20 < t \leq 22\)[/tex] | 8 |
| [tex]\(22 < t \leq 24\)[/tex] | 5 |
| [tex]\(24 < t \leq 28\)[/tex] | 3 |

### Step 2: Calculate the Total Number of Observations
To find the total number of observations, we sum up all the frequencies:

[tex]\[ 4 + 10 + 8 + 5 + 3 = 30 \][/tex]

So, the total number of observations is 30.

### Step 3: Calculate the Cumulative Frequency
Next, we need to calculate the cumulative frequency for each class interval:

| Class Interval | Frequency | Cumulative Frequency |
|---------------------|-----------|----------------------|
| [tex]\(14 < t \leq 18\)[/tex] | 4 | 4 |
| [tex]\(18 < t \leq 20\)[/tex] | 10 | 4 + 10 = 14 |
| [tex]\(20 < t \leq 22\)[/tex] | 8 | 14 + 8 = 22 |
| [tex]\(22 < t \leq 24\)[/tex] | 5 | 22 + 5 = 27 |
| [tex]\(24 < t \leq 28\)[/tex] | 3 | 27 + 3 = 30 |

### Step 4: Find the Median Class Interval
The median position is calculated as:

[tex]\[ \frac{\text{Total Number of Observations}}{2} = \frac{30}{2} = 15 \][/tex]

Now, we look for the class interval in which the cumulative frequency just surpasses the median position of 15:

- Cumulative frequency of the first class interval (4) is less than 15.
- Cumulative frequency of the second class interval (14) is still less than 15.
- Cumulative frequency of the third class interval (22) is greater than 15.

So, the median class interval is [tex]\(20 < t \leq 22\)[/tex].

### Step 5: Calculate an Estimate for the Mean Maximum Temperature
To estimate the mean, we first need the midpoints of each class interval. These midpoints are calculated as follows:

- For [tex]\(14 < t \leq 18\)[/tex]: midpoint is [tex]\( \frac{14+18}{2} = 16.0\)[/tex]
- For [tex]\(18 < t \leq 20\)[/tex]: midpoint is [tex]\( \frac{18+20}{2} = 19.0\)[/tex]
- For [tex]\(20 < t \leq 22\)[/tex]: midpoint is [tex]\( \frac{20+22}{2} = 21.0\)[/tex]
- For [tex]\(22 < t \leq 24\)[/tex]: midpoint is [tex]\( \frac{22+24}{2} = 23.0\)[/tex]
- For [tex]\(24 < t \leq 28\)[/tex]: midpoint is [tex]\( \frac{24+28}{2} = 26.0\)[/tex]

Next, we calculate the total sum of the products of frequencies and their corresponding midpoints:

[tex]\[ (4 \times 16.0) + (10 \times 19.0) + (8 \times 21.0) + (5 \times 23.0) + (3 \times 26.0) \][/tex]

[tex]\[ = 64.0 + 190.0 + 168.0 + 115.0 + 78.0 = 615.0 \][/tex]

Finally, the estimated mean maximum temperature is:

[tex]\[ \frac{\text{Total Sum of the Products}}{\text{Total Number of Observations}} = \frac{615.0}{30} = 20.5^\circ C \][/tex]

### Summary of Results
- The class interval that contains the median is [tex]\(20 < t \leq 22\)[/tex].
- The estimated mean maximum temperature is [tex]\(20.5^\circ C\)[/tex].