To determine the marginal relative frequency for wood frogs that were studied, we need to follow these steps:
1. Aggregate the Total Number of Frogs Studied:
Based on the table provided:
- For Dragonflies: 24 (Bullfrogs) + 12 (Tree Frogs) + 15 (Wood Frogs)
- For Worms: 19 (Bullfrogs) + 20 (Tree Frogs) + 30 (Wood Frogs)
Summing these up:
[tex]\[
24 + 12 + 15 + 19 + 20 + 30 = 120
\][/tex]
So, the total number of frogs studied is 120.
2. Calculate the Total Number of Wood Frogs Studied:
From the table:
- 15 Wood Frogs prefer Dragonflies
- 30 Wood Frogs prefer Worms
Summing these up:
[tex]\[
15 + 30 = 45
\][/tex]
So, the total number of Wood Frogs studied is 45.
3. Calculate the Marginal Relative Frequency:
The marginal relative frequency is the ratio of the number of Wood Frogs studied to the total number of frogs studied, expressed as a percentage. This can be calculated as follows:
[tex]\[
\frac{\text{Number of Wood Frogs}}{\text{Total Number of Frogs}} \times 100 = \frac{45}{120} \times 100
\][/tex]
4. Perform the Division and Multiplication:
[tex]\[
\frac{45}{120} \approx 0.375 \implies 0.375 \times 100 = 37.5\%
\][/tex]
So, the marginal relative frequency for wood frogs that were studied is [tex]\(37.5\%\)[/tex].
Thus, the correct answer is:
[tex]\[ 37.5\% \][/tex]