In the context of a hypothesis test for two proportions, which of the following statements about the pooled sample proportion, , is/are true? I. It estimates the common value of p1 and p2 under the assumption of equal proportions. II. It is obtained by averaging the two sample proportions 1 and 2. III. It is equal to the proportion of successes in both samples combined.

The statements that are true about a hypothesis test for two proportions are:

I. It estimates the common value of p1 and p2 under the assumption of equal proportions.

II. It is obtained by averaging the two sample proportions 1 and 2.

Step-by-step explanation:

We use the two sample proportion z-test to determine whether the proportions of the two groups differ. This test calculates the range of values that is likely to include the differences between the sample proportions of p1 and p2.

the expected value of the random variable : 0, 1 and 2

step-by-step explanation: