An apartment hunter is shopping for either a one-bedroom or two-bedroom apartment in different apartment buildings. She wants to estimate the additional amount she would have to pay, on average, for a two-bedroom apartment versus a one-bedroom apartment. The table shows the prices, in dollars, for one- and two-bedroom apartments from the nine buildings she visited.   What is the 99% confidence interval for the true mean difference between two-bedroom and one-bedroom apartments for apartment buildings like the ones in the sample? A. 2 samp t-int 99% B. (106.12, 658.32) C. (198.46, 565.99) D. (255.93, 508.51) E. 2 samp t-int 95%

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 + ...