Final answer:
The probability that a randomly selected sample of size has a mean greater than 21.1 is 1%.
Step-by-step explanation:
To find the probability that a randomly selected sample of size has a mean greater than 21.1, we need to use the properties of the normal distribution. Firstly, we need to find the z-score corresponding to a mean of 21.1 using the information given. From the table or calculator, we find that a z-score of 2.326 corresponds to an area of 0.99 to the left. Since we want the mean to be greater than 21.1, we need to find the area to the right of 2.326. This can be found by subtracting 0.99 from 1, which gives us an area of 0.01. Therefore, the probability that a randomly selected sample of size has a mean greater than 21.1 is 0.01 or 1%.