Final answer:
To calculate the average number of products sold per week, multiply the number of cars sold by the corresponding frequency, sum up the results, and divide by the total number of car salespersons.
Step-by-step explanation:
In order to determine whether the average number of products sold per week has decreased, we need to analyze the data provided. The data shows that 14 car salespersons generally sell three cars, 19 sell four cars, 12 sell five cars, nine sell six cars, and 11 sell seven cars. To calculate the average number of products sold per week, we can multiply the number of cars sold by the corresponding frequency and sum up the results. Then, we divide the total by the total number of car salespersons:
Average = (3 * 14 + 4 * 19 + 5 * 12 + 6 * 9 + 7 * 11) / 65
By performing the calculations, we find that the average number of products sold per week is approximately 4.908 cars.