The z-score of the certain data point is calculated through the equation,
z-score = (x - m)/s
where x is the given data point, m is the mean, and s is the standard deviation.
Substituting the known values from the given,
z-score = ($0.99 - $0.88) / $0.05
z-score = 2.2
The answer to this item is 2.2.
