A median is the middle value after all observations are in order. A dot plot puts the values in order from left to right, and every dot counts, even when dots are stacked. Count in from both ends to find the middle; counting only the different values can put you at the wrong position.
Hints
- Hint 1
Each dot on a dot plot stands for one observation. A stack means the value occurs more than once, so write the value once for each dot. What list do you get from left to right?
- Hint 2
The median is the middle observation in order, not the middle tick mark on the axis. With seven dots, how many dots must lie on each side of the middle one?
Step-by-step
Count to the middle dot
Step 1Read all the values
No Desmos needed. The dot plot already puts the calls in order. Each dot represents one sales representative, so the two dots above count separately. Reading left to right gives .
- Step 2
Find the middle position
The median is the middle value in order. There are dots, so the fourth dot is the middle one: three dots come before it and three come after it.
- Step 3
Read the fourth dot
and fill the first two positions. The two dots at fill the third and fourth positions. So count stacked dots separately when finding the middle: the median is sales calls. Choice B.