We study some basic data analysis methods.

There are two common days to measure the center of a data set: the mean, and the median.

The Mean of a data set is the sum of all data values divided by the total number of data.

While the mean tells the average, we need more to know how the data are distributed, or data deviation.

The mean absolute deviation (MAD) of a data set is the total distance of all data values from the mean value divided by the number of values. The bigger this values is, the more scattered the data; the smaller this value is, the more clustered the data.

Mean does not always tell a good story of the average, as some smaller set of data can affect the outcome. Another way to calculate the center is the median, which is the middle value when the data are are arranged in order from the smallest to the largest.

The mean, the median, and the MAD, together they give us better understanding of the data.

Homework:

P50, #4(i)(iii)(v)(vii), #5, #6(b, d, f, h), #7, #16 – #20.