Question

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. Interpret this value.

a. The expected or average costs for all weekly rat purchases is $20.00

b. Most of the weeks resulted in rat costs of $20.00

c. The median cost for the distribution of rat costs is $20.00

d. The rat cost that occurs more often than any other is $20.00

Answer 1

a. The expected or average costs for all weekly rat purchases is $20.00

Explanation:

a. A mean value of $20.00 means that over a period of 52 weeks, the company can expect to spend $20.00 per week on rat purchases.

b. This is incorrect since individual values don't interfere in the mean. For instance, if half the weeks had a cost of $19.00 and the other half had a cost of $21.00, the mean cost would still be $20.00 even though no particular week had a $20.00 cost

c. Incorrect. The median is the central value in a distribution; the median and the mean are not necessarily the same.

d. Incorrect, same as item b.