Here is my data file

 seconds        data
 (x-axis       ( y axis
  points)      points)
3.880000,       20
3.920000,       10
3.960000,       20
4.000000,       20
4.080000,       20
4.120000,       20
4.570000,       20
4.620000,       10
4.650000,       10
4.690000,       10
4.750000,       20
 .
 .
 .
and so on

I want to plot points in column 2 at positions specified by column 1

ie I want 20 , 10 , 20 20, 20 etc to be present at 3.88 , 3.92, 3.96 on xaxis

Can anybody tell me how to do this ?