A clinical trial was conducted to test the effectiveness of a drug for treating insomnia and older subjects. Before treatment 21 subjects heading mean wait time of 100.0 minutes. After treatment the 21 subjects have a mean wig time of 91.6 minutes and a standard deviation of 20.3 minutes. Assume that the 21 sample values appear to be from a normally distributed population and construct a 99% confidence interval estimate of the main week time for a population with drug treatments. What does the results of just about the mean weight time of 100.0 minutes before the treatment? Does the drug appear to be effective? A. Construct the 99% confidence interval estimate of mean we time for a population with the treatment.  B. What does the results of just about the mean with time of 100.0 minutes before the treatment? Does the drug appear to be effective?

Definition Definition Measure of central tendency that is the average of a given data set. The mean value is evaluated as the quotient of the sum of all observations by the sample size. The mean, in contrast to a median, is affected by extreme values. Very large or very small values can distract the mean from the center of the data. Arithmetic mean: The most common type of mean is the arithmetic mean. It is evaluated using the formula: μ = 1 N ∑ i = 1 N x i Other types of means are the geometric mean, logarithmic mean, and harmonic mean. Geometric mean: The nth root of the product of n observations from a data set is defined as the geometric mean of the set: G = x 1 x 2 ... x n n Logarithmic mean: The difference of the natural logarithms of the two numbers, divided by the difference between the numbers is the logarithmic mean of the two numbers. The logarithmic mean is used particularly in heat transfer and mass transfer. ln x 2 − ln x 1 x 2 − x 1 Harmonic mean: The inverse of the arithmetic mean of the inverses of all the numbers in a data set is the harmonic mean of the data. 1 1 x 1 + 1 x 2 + ...