To calculate the probability that Jorelle will pick the letter R based on the observed frequency, you can use the formula for probability:
\[ \text{Probability (P)} = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} \]
From the data provided:
- Frequency of R = 30
- Total frequency (number of trials) = 20 + 25 + 30 + 10 + 15 = 100
Now, substituting these values into the probability formula:
\[ P(R) = \frac{30}{100} = 0.30 \]
To convert this probability into a percentage, multiply by 100:
\[ P(R) = 0.30 \times 100 = 30% \]
Therefore, the probability that Jorelle will pick the letter R is 30%.