List out the parameters of the population that you feel are important to the definition of "representativeness" (i.e., gender and age).
If the population is say, 65% female, 35% male, then the sample should break down closely to that.
For age, break down the population into age categories or actual age numbers, then compare the % of each in the sample to the % of each in the population.
Do the same exercise for "function" and "hours worked per week" and anything else you feel is important.....
You could just use judgment in determining whether the sample %'s are "close enough" to the population %'s, or you could run a z-test to statistically compare the sample % to the known population %.