Bo Derek calculates that she needs a sample size of 200, given
the sampling error, population variance and required z-score for
95% confidence. However, she learns later that the true variance is
half of what she used in the sample size calculation. Based on this
new value of variance, new sample size required will now be
________.
100
800
400
50
A college dean wants to determine the average time it takes a
student to get from one class to...