Final answer:
To determine the original mean of 200 items in Mathematics, one must sum the values of all items and divide by 200.
Step-by-step explanation:
The question "What was the initially calculated mean of 200 items?" relates to the subject of Mathematics and appears to be at the high school grade level based on the use of the term mean and the context of dealing with a set of 200 items. To calculate the mean (average) of a set, one would typically sum all the values of the items and then divide by the number of items.
The provided information does not include specific numerical values to directly calculate the mean, but instead provides general context about sampling, realistic numbers, units of measurement, and population estimates. Therefore, the answer to the student's question would require additional specific data regarding the 200 items. The process for finding the mean would involve adding up the values of the 200 items and then dividing that total by 200.