Final answer:
The probability that a standard normal variable will be exactly equal to -0.68 or any single value is 0 because a continuous probability distribution assigns a probability of zero to individual points.
Step-by-step explanation:
The probability that a standard normal variable is exactly equal to any single value, like -0.68, is actually 0. This is because the standard normal distribution, like any continuous probability distribution, assigns a probability of zero to every individual point. To find the likelihood of a variable falling within a certain range, you would instead look at the area under the normal curve between two points, which corresponds to the integral of the density function over that interval. In this case, however, an individual point has zero width, and thus the area (and therefore the probability) is zero.