Question 1
An honest coin is tossed n times. Let the random variable X denote the number of heads tossed. How many tosses n are required to be 97.5% certain that X will be less than
+ 20?
◦ 100
◦ 800
◦ 400
◦ 200
◦ none of these
Question 2
In a survey of 1000 Americans, 850 said that they own a cell phone. Assume that the survey was properly conducted and that the 1000 people surveyed represent an unbiased sample of the entire population. Estimate the standard error for this survey.
◦ ≈ 0.1%
◦ ≈ 11.1%
◦ ≈ 11.3%
◦ ≈ 12.75%
◦ ≈ 1.1%