Question

7. A recent report states that 89% of Americans consider themselves above average drivers. A local newspaper is planning on conducting a survey to investigate whether this is true locally. If the newspaper assumes that the 89% claim is true and plans to use the normal approximation to calculate probabilities associated with their sample proportion, which sample size would be most appropriate

Answer 1

The available options are

A) 10

B) 11

C) 30

D) 91

E) The number depends on the size of the population.

Answer:

91

Explanation:

Given that for the normal approximation, we need that:

np > 5 and np(1-p) > 5

Hence, we have

n = 91

91*0.89 = 80.99

91*0.89*0.11 = 8.9089 > 5

Therefore the answer gotten is satisfactory or satisfies the condition, and which makes 91 the accurate solution.

The other options, when calculated is less than 5