13. B) Non-linear
As per its definition, linear means line. If a function is linear, then one can plot it out, and the resulting graph will be a line. This is not the case for the given function, therefore, it is non-linear.
14. A) Yes
An outlier is a data point that does not fit in with the result. It is not in the general region that the rest of the data points fall in. In the given function, the point (0.5, 3) is not in the general region that the rest of the points are in, therefore, it is an outlier.
15. B) Yes, there seems to be two distinct groups of data.
As one can see there appears two be two groups of data. One of them is towards the upper left corner, whereas the other seems to be towards the lower right corner.