Final answer:
The function y = -1/3 log (1/3x) is compressed vertically by a factor of 1/3, which scales the y-values of the function accordingly.
Step-by-step explanation:
The function in question is y = -1/3 log (1/3x), and it involves properties of logarithmic transformations. When a function includes a logarithm with a coefficient, in this case -1/3, before the log term, it represents a vertical compression or stretch, depending on the value of the coefficient. The negative sign indicates there is also a reflection over the x-axis.
However, the coefficient 1/3 in this case indicates that the original log function is compressed vertically by a factor of 1/3. This is due to the logical rule that any stretching or compressing by a factor a will alter the function's output by that factor, essentially scaling the y-values of the function by 1/3.