ide ponuth A researcher hypothesizes that ambient air carbon should be higher in the winter than they are in the summer. The reasoning behind this hypothesis that a major source of carbon monoxide in the air is from the incomplete combustion of fuels, and fuels tend to burn less efficiently at low temperatures. Moreover, it is felt that the stagnant winter a is more likely to trap the pollution. In order to investigate this hypothesis, the data set in DS 9.7.12 is collected which shows the ambient air carbon monoxide pollution levels (parts per million) for ten Sunday mornings in the middle of winter and ten Sunday mornings in the middle of summer.

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 + ...