I'm not sure about the given data but I plotted the scatter plot based on what I understand on how the data should be presented.
Time (years)
3, 6, 9, 12, 15, 18, 21, 24
Number of participants(x1000)
22, 25, 28, 14, 17, 20,15, 9
Attached is the scatter plot created online.
x = time (years)
y = number of participants
All the place values of 12, 354.897 are as follows: 12 thousands, 3
hundred, 5 tens, 4 ones, 0.8 tenths .09 hundredths, .007 thousandths.
The is 20 characters long
Here look at this for my answer...