The two way table below contains some completely fictitious data on the the types of computers favoured by men and women.

Laptop 
Desktop 
Tablet 
Total 
Men 
31 
17 
40 
88 
Women 
12 
42 
17 
71 
Total 
43 
59 
57 
159 
Events A and B are independent if(1)
For the table above take A as 'a person picked at random favours a desktop', and event B as 'a person picked at random is a woman'.
The probability that a person picked at random favours desktops isand the probability that a person picked at random is a woman is
The number of women who favour desktops is 42 out of a total of 159, so the probability that a person picked at random is a woman favouring a desktop is
These probabilities do not satisfy condition (1) for indepence since