To find the proportion of Marok’s pulse rates above 160 beats per minute, we standardize the value using the formula for the z-score:

\(z = \frac{X - \mu}{\sigma}\)

where \(X = 160\), \(\mu = 148.6\), and \(\sigma = 18.5\).

\(z = \frac{160 - 148.6}{18.5} = 0.616\)

We need to find \(P(X > 160) = P(z > 0.616)\).

Using the standard normal distribution table, \(P(z > 0.616) = 1 - P(z < 0.616) = 1 - 0.7310 = 0.269\).

Thus, the proportion of pulse rates above 160 beats per minute is 0.269.