5C) We will have to choose the best measure of central tendency for this data set.
The mean has a value of 215 while the median is 212.5.
In this case, as the data don't have clear outliers and it is also centered, the most appropiate measure is the mean.
5D) In this case, we are introducing a value of 784 seconds to the data set.
The mean is now:
The median is equal to 225, which is the 6th value of the set when sorted.
As we are using the mean, this is sensible to outliers and can be affected by its value much more than the median, which does not care about the absolute value of the extreme points but the value of the data points in the center.
Then, we can imagine that given that the maximum value was 265, and given a mean of 215, a value of 784 is obviously an outlier and does not belong to the group of normal observations of this data set.