Answer:
Mean=74.78
Median=78
Mode=78
Explanation:
1. First order the data set from the from least to greatest:
15 34 71 75 75 78 78 78 82 87 90 90 94 100
2. To find the mean, add all the numbers and divide the result by the number of data.


3. Since you have an even data set, to find the median you take the two values of the middle of the data set and find the average between them:



4. The mode is the most repeated value, in this case, value 78 is repeated 3 times so this value is the mode of the data set.