Answer:
A. Model B with the smaller standard deviation is preferable, because the smaller value implies that the mean is a more reliable representation of maintenance costs.
Explanation:
The standard deviation is a measure of the variability of a dataset about a mean value. Larger values of standard deviation implies that the values varies Hugely about the mean whole smaller variability measure values mean that the data only varies a little about the mean. The implication of having a large variability value is that, low and high values in the data can be very different from the mean values, hence, lowering the reliability of Mean value. The lesser varibality gives the mean more reliability as a measure of centre