Researchers claim that the birth rate in Bonn, Germany, is higher than the national average. A random sample of 1800 Bonn residents had 18 births, whereas a random sample of 3000 people from all over Germany had 15 births during the same year. Test the researchers' claim using a 0.10 level of significance. Let Bonn residents be population 1 and let people from all over Germany be population 2. Step 2 of 3: Compute the value of the test statistic.
a) Z = 1.50
b) Z = -1.50
c) Z = 0.50
d) Z = -0.50
