Final answer:
To determine whether the number of girls is significantly high or low, we can use hypothesis testing which involves calculating a test statistic, comparing it to a critical value, and making a conclusion based on the results.
Step-by-step explanation:
In order to determine whether the number of girls is significantly high or low, we can use the concept of hypothesis testing. Let's state our null hypothesis as: The proportion of girls in the population is equal to the natural ratio of girls to boys (100:105). Our alternative hypothesis can be: The proportion of girls in the population is significantly different from the natural ratio.
To conduct a hypothesis test, we need to calculate the test statistic and compare it to the critical value. The test statistic can be calculated as:
test statistic = (observed proportion - expected proportion) / standard error of proportion
Once we have the test statistic, we can find the critical value from the appropriate distribution (e.g., Z-distribution for large sample sizes) and compare it to the test statistic to make a conclusion about the null hypothesis. If the test statistic falls within the critical region, we reject the null hypothesis and conclude that the number of girls is significantly different from the expected ratio.