hypothesis test ,test statistic wrong!

Hi,q is: A margarine firm has invited 200 men and 200 women to see if they can distinguish margarine from butter. It is found that 120 of the women, but only 108 of the men can. Investigate whether there is any evidence of a sex difference in taste discrimination. I did x-b(200,120/200) converting to normal gaves me a test statistic 1.13,,,,i was just wandering if anyone knew how to get the test statistic they had in the back of the book of 1.21 in order to confirm there is no sex discrimination supposedly at the standard 5%? thanx!