To calculate the relative frequency of people age 12–15 who had over 500 messages, we first need to determine the total number of people in the 12–15 age group and the number who had over 500 messages.
From the table, for the age group 12–15:
- Number of people with 0–200 messages: 24
- Number of people with 201–500 messages: 47
- Number of people with over 500 messages: 78
Now, we calculate the total number of people in the 12–15 age group:
\[ \text{Total} = 24 + 47 + 78 = 149 \]
Next, we find the relative frequency of the people age 12–15 who had over 500 messages:
\[ \text{Relative Frequency} = \frac{\text{Number with over 500 messages}}{\text{Total number of people}} \]
Substituting the values we found:
\[ \text{Relative Frequency} = \frac{78}{149} \]
Calculating this value gives:
\[ \text{Relative Frequency} \approx 0.5235 \]
To express this as a percentage, we multiply by 100:
\[ \text{Relative Frequency Percentage} \approx 0.5235 \times 100 \approx 52.35% \]
Rounding this to the nearest tenth gives us:
\[ 52.4% \]
Therefore, the relative frequency of the people age 12–15 who had over 500 messages is approximately 52.4%.