Final answer:
To calculate the proportion of the means of a sampling distribution that would be less than 4.0, use the z-score formula.
Step-by-step explanation:
To calculate the proportion of the means of a sampling distribution that would be less than 4.0, we need to find the z-score for 4.0 using the formula:
z = (x - u) / (o / sqrt(n))
where x is the value we want to calculate the proportion for (4.0 in this case), u is the population mean (5), o is the standard deviation (2), and n is the sample size (3).
Plugging in the values, we get:
z = (4.0 - 5) / (2 / sqrt(3)) = -0.866
We can then use a standard normal distribution table to find the proportion associated with this z-score. The proportion is approximately 0.1932, which is closest to option c) 0.1922.