Use the following stem-and-leaf plot, representing the starting salary (in thousands of dollars) of ten friends after college graduation, to...

For a stem and leaf plot, the number to the left of the bar is generally the stem and the numbers to the right of the bar are the leaves. The stem is the first digit(s) and the leaves are the next significant digit. The leaves are not separated by commas.

For this plot the data are 17,19,20,21,23,23,24,30,33,40

Note that the key tells us that 1|7 is 17. (It could have been 170 if the key was 1|7=170 or .17 if the key had been 1|7=.17 etc...)

Since there are 10 data items the median is the arithmetic mean of the 5th and 6th numbers of the ordered list -- here the median is 23. The mode is the number(s) that occur the most often -- here the mode is 23.

To find the mean we add the numbers and divide by 10 (the number of elements).

The lower quartile is the median of the lower half (the first 5 elements) and is 20 while the upper quartile is the median of the upper half which is 30.