A current survey reported that in sample of 300 students who attend two-year colleges, 105 work at least 20 hours per week. Additionally, in a sample of 225 students attending private four-year universities, only 20 students work at least 20 hours per week. What is the test value foe a test of the difference between these two populations proportions?
A) 6.95
B) 7.61
C) 2.38
D) 4.18