Final answer:
The correct statement is b: An estimate of the average revenue for all Fortune 500 companies is 8787.42 ($ millions), as this is an average based on the sample given, and not a definitive average for all companies.
Step-by-step explanation:
The student has presented a data set for the revenues of five Fortune 500 companies and wants to understand which statement about these revenues is correct. To answer that, first, we need to calculate the average revenue of these five companies. By adding the given revenues (7505.0, 2904.7, 7208.4, 6819.0, and 19500.0 million dollars) and dividing the sum by five, we get 8787.42 million dollars. This figure is the average for only these five companies, not for all Fortune 500 companies. Therefore, the correct statement is b: An estimate of the average revenue for all Fortune 500 companies is 8787.42 ($ millions).
This is because with only five companies' data, we're making an estimate based on a sample, not a definitive average for the entire list of Fortune 500 companies. Statements a, c and d are incorrect as they either state the average as a fact for all companies, suggest the same average for another distinct set of companies, or make an assumption about the distribution of revenues across all companies without sufficient data.