Final answer:
The appropriate hypothesis test to use in this situation is the two sample t-test. It is used to compare the means of two independent groups.
Step-by-step explanation:
The appropriate hypothesis test to use in this situation is the two sample t-test. This test is used to compare the means of two independent groups to determine if they are statistically different from each other. In this case, we are comparing the mean proportions of bicycle-related head injuries in South Australia and Victoria.
To perform the two sample t-test, we need to calculate the sample means, sample standard deviations, and the sample sizes for both South Australia and Victoria. We can then use these values to calculate the t-statistic and compare it to the critical value to determine if there is enough evidence to reject the null hypothesis.