The Red Cross wanted to know whether an ad campaign designed to persuade people to donate blood actually increased blood donations.For a sample of N = 4 blood donation centers,the mean increase in blood donations was 10 pints,with a standard deviation of 2 pints.If the Red Cross could collect data from the entire population of blood donation centers,what would one expect the population standard deviation to be?
A)2
B)2.31
C)2.67
D)20

Question

Quizplus · Accepted Answer

The best estimate for the population standard deviation would be the sample standard deviation divided by the square root of the sample size (since we are assuming that the population follows a normal distribution). So, the estimated population standard deviation would be:

2 / sqrt(4) = 2 / 2 = 1

However, this is just an estimate, and it may not be a perfect representation of the population. In order to get a more accurate estimate of the population standard deviation, we could collect more data from a larger number of blood donation centers. The answer choices given do not include this estimated value of 1, so we need to choose the closest one, which is B, 2.31.

The Red Cross Wanted to Know Whether an Ad Campaign