\( 3 d) \) Which mean is reasonable for the data set? \( \qquad 15,25,60,30,45\} \)

To determine which mean is reasonable for the data set \( \{ 15, 25, 60, 30, 45 \} \), we first calculate the mean. By summing up the numbers, we get \( 15 + 25 + 60 + 30 + 45 = 175 \). Dividing this by the number of values (5), the mean is \( 35 \). Since the data set has a significantly higher outlier (60), the median, which is 30, might be a more representative measure of central tendency in this case. Another useful concept is the "trimmed mean," which involves removing a certain percentage of the highest and lowest values and then calculating the mean of the remaining data. For this data set, you might trim the lowest (15, 25) and the highest (60) values and find the mean of the middle values (30, 45), which gives a trimmed mean of 37.5—offering a potentially more accurate representation than the traditional mean.