To find the joint relative frequency of elementary age students who prefer winter, we first need to identify the total number of students surveyed and the number of elementary age students who prefer winter.
From the table:
- The number of elementary age students who prefer winter is 84.
- The total number of students surveyed is 251.
The joint relative frequency is calculated using the formula:
\[ \text{Joint Relative Frequency} = \frac{\text{Frequency of specific group}}{\text{Total frequency}} \times 100 \]
Substituting the values:
\[ \text{Joint Relative Frequency} = \frac{84}{251} \times 100 \]
Calculating the above fraction:
\[ \frac{84}{251} \approx 0.3347 \]
Now, multiplying by 100 to convert it to a percentage:
\[ 0.3347 \times 100 \approx 33.47 \]
Rounding to the nearest whole number, the joint relative frequency of elementary age students who prefer winter is:
33 percent.