# What is the error rate for random guessing?

I am studying for my Machine Learning exam. In sample exam questions, there is a specific one that I could not understand:

And the question is: "What is the error rate for random guessing?"

I could not understand the question, can anyone explain it to me?

Random guessing of value of whcih column? For example random guessing the gender of each row is: probability of it is male but guess female + vice versa which is $$\frac{7}{10}\times\frac{1}{2} + \frac{3}{10}\times \frac{1}{2} = \frac{1}{2}$$ and it means the error of random guessing the value of Gender is $$50\%$$. Also you can compute for the others by the possible value for each column. For example for the Hair Length the error would be $$\frac{2}{3}$$ or $$66.66\%$$.