FRAME 27.

Suppose gathering all this data were very expensive. An alternative approach would be to

take a sample from this population. Assume the observations 37, 58, 35, 54 were chosen as a

sample from the population above.

a. Compute the mean. _______________

b. Is this a sample or population mean? _______________

FRAME 28.

Compute the mean for the following samples.

Sample 1: 22, 29, 22, 7, 34. _________________

Sample 2: 22, 29, 22, 7, 10,000. ________________

FRAME 29.

The second measure of central tendency is called the MEDIAN. The median is a positional

average. It is determined by arranging the data in ascending or descending order and locating

the middle value.

If there is an even number of observations in our data, we find the median by taking the mean

of the MIDDLE two values. If there is an odd number of observations, there will always be one

value in the data set that is the median.

For example, suppose we have the following nine observations: 1, 22, 29, 23, 7, 34, 14, 17, 31.

We would find the median by arranging the data in ascending (or descending) order and selecting

the middle value. Putting the values in ascending order gives: 1, 7, 14, 17, 22, 23, 29, 31, 34. The

median or middle value in this ordered list is 22. There are four values larger than 22 and four

values smaller than 22. If we arrange the data in descending order, the result would be the same.

Try it.

QUESTION:

What is the median of the following eight observations:

8, 24, 28, 19, 7, 31, 2, 22 ________________