If there are an equal amount of yellow, blue, green, and red marbles in a bag of 32 marbles, then there are \( \frac{32}{4} = 8 \) marbles of each color.
The probability of drawing a blue marble from the bag is the number of blue marbles divided by the total number of marbles. Thus, the probability of drawing a blue marble is:
\[ P(\text{blue}) = \frac{8}{32} = \frac{1}{4} \]
If Ed draws 4 marbles, we can predict the expected number of blue marbles he will draw by multiplying the probability of drawing a blue marble by the number of draws:
\[ \text{Expected number of blue marbles} = P(\text{blue}) \times \text{number of draws} = \frac{1}{4} \times 4 = 1 \]
Therefore, the predicted number of blue marbles drawn is:
1