I am sorry but you seen to have just demonstrated your total ignorance of the actual argument.
There is no sensible argument that there is a not a difference in the median or average (mode) aggragated pay of all men and women.
That's
not the issue. Its well established that on average mens aggragated pay is higher than women's and that this is generally also the case when the data is broken down into some subsets for different industries.
The argument is over why this is the case. Certain feminists argue the 'wage' gap (more accurately earnings gap) is because women are paid less for doing the same jobs.
Which is almost total nonsence as we know that women and men dont do the same types of jobs when looked at as groups.
One statistic that should give you a hint of this is the circa 96
% rate of male fatalities in the workplace.
You and the Guardian article are comparing apples to oranges... .
As to your wifes friend what job(s) , what role(s) , what location(s) are we taking about
Given your lack of a grasp as to why men and women, on average, receive different wages I'm not at all confident that any further data you supply won't just confirm my earlier suspicions.