Answer:
The expected or average costs for all weekly rat purchases is $20.00
Explanation:
A lab at the DeBakey Institute orders 150 rats a week for each of the 52 weeks in the year for experiments that the lab conducts.
Suppose the mean cost of rats used in lab experiments turned out to be $20.00 per week.
Means means average. We can say that the average cost is $20 per week, that will give $20 as an average for the year.
Hence, the answer is : The expected or average costs for all weekly rat purchases is $20.00