where po and pc represent the proportion of fruit flies alive at the end of the given time frame of those eating organic food and those eating conventional food, respectivly. We have n1 = n2 = 500. Show all remaining details in the test using a 5% significance level. After 20 days 275 of the 500 fruit flies eating organic raisins are still alive, while 170 of the 500 eating conventional raisins are still alive. What is the test statistic