Answer:
The calculated z-score is -1.13, which is not less than the critical value of -1.96, so we fail to reject the null hypothesis.
To find the calculated z-score, we use the formula:
z = (P1 - P2) / √(p(1-p)(1/n1 + 1/n2))
In this case, P1 represents the proportion of type O in the first sample (15/40), P2 represents the proportion of type O in the second sample (20/40), and p represents the pooled proportion of type O (35/80).
Let's calculate the z-score:
z = (15/40 - 20/40) / √((35/80)(1 - 35/80)(1/40 + 1/40))
= (-5/40) / √((35/80)(45/80)(1/40 + 1/40))
= -1.13
The calculated z-score is -1.13.
To interpret the z-score, we compare it to the critical value at a 95% confidence level. The critical value for a 95% confidence level is -1.96. Since the calculated z-score (-1.13) is not less than the critical value (-1.96), we fail to reject the null hypothesis.
Therefore, based on the given information, we fail to reject the null hypothesis. So the correct answer is A.
Explanation:
<3