Question

The Bradenton Post polled 1,356 adults in the city to determine whether they wet their toothbrush before they put toothpaste on it. Of the respondents, 54% said they wet it first. Suppose 68% of all adults actually wet their toothbrush first. What are the mean and standard deviation of the sampling distribution?

The mean is 0.54 and the standard deviation is 0.0135.
The mean is 0.54 and the standard deviation is 0.0127.
The mean is 0.68 and the standard deviation is 0.0224.
The mean is 0.68 and the standard deviation is 0.0135.
The mean is 0.68 and the standard deviation is 0.0127.

Answer 1

The mean is 0.54 and the standard deviation is 0.0135.

Explanation:

The mean is 0.54. The standard deviation is calculated using that mean:

s = √(p (1 − p) / n)

s = √(0.54 (1 − 0.54) / 1356)

s = 0.0135