Q.2 - The Practice of Statistics for AP

Question

The Gallup Poll has decided to increase the size of its random sample of voters from about $1500$ people to about $4000$ people right before an election. The poll is designed to estimate the proportion of voters who favor a new law banning smoking in public buildings. The effect of this increase is to

(a) reduce the bias of the estimate. 

(b) increase the bias of the estimate. 

(c) reduce the variability of the estimate. 

(d) increase the variability of the estimate. 

(e) have no effect since the population size is the same 

Step-by-Step Solution

Answer

The correct answer is (c) Reduce the variability of the estimate. 

Step 1 Given Information

Size the random sample of voters $=1500$

Size of the random sample of increased voters $=4000$$=4000$

Step 2 Explanation

We know that the sampling procedures always cause bias and the bias is not influenced by the sample size.

Since a larger sample gives more information about the respective population; if the sample size increases then the variability is reduced.

Hence, the correct answer is (c)

That is reduce the variability of the estimate.