To find the proportion of rocky-soil farmers who choose to produce peppers, we need to calculate the relative frequency of pepper production among rocky-soil farmers.
The number of rocky-soil farmers producing peppers is 150, and the total number of rocky-soil farmers is 250.
The formula for relative frequency is:
\[ \text{Relative Frequency} = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} \]
Substituting in the values:
\[ \text{Relative Frequency} = \frac{150}{250} = 0.6 \]
Now, to express this as a percentage, we multiply by 100:
\[ 0.6 \times 100 = 60.0% \]
Thus, the percentage chance that farmers with rocky soil prefer growing peppers is 60.0%.
The correct response is: 60.0%.