To predict the diastolic pressure using the equation \( y = 8.2673 + 0.5914x \), where \( x \) is the systolic pressure, we can substitute \( x = 133 \) into the equation.
\[ y = 8.2673 + 0.5914(133) \]
First, we calculate \( 0.5914 \times 133 \):
\[ 0.5914 \times 133 = 78.6072 \]
Now, we can substitute this back into the equation:
\[ y = 8.2673 + 78.6072 = 86.8745 \]
Now, rounding to one decimal place, we find:
\[ y \approx 86.9 \]
Thus, the predicted diastolic pressure for a patient whose systolic pressure is 133 millimeters is 86.9 mmHg.