Final answer:
The exponential distribution is distinguished from the normal distribution by being right-skewed, where there are more small values and fewer large values, and only non-negative values are present. Option a.
Step-by-step explanation:
The characteristic that distinguishes the exponential distribution from the normal distribution is that the exponential distribution is inherently right-skewed. This means option a. 'the exponential distribution has a right skew' is correct.
In a right-skewed or positively skewed distribution like the exponential, there are more small values with the frequency of values decreasing as they get larger.
The mean of a right-skewed distribution is greater than the median, and both of these are often greater than the mode. By contrast, the normal distribution is symmetrical, with the mean, median, and mode all located centrally.
The exponential distribution is used to describe the time between events in a Poisson process and is an appropriate model for various types of real-world phenomena, such as the amount of time until a radioactive particle decays, or the time between phone calls received at a call center.
Unlike the symmetrical normal distribution, the exponential distribution only deals with non-negative values (i.e., x ≥ 0).
Option a.