Need a further explanation fir b ii). The answer written is from the solutions given from the text book. I couldn't figure out where those y and x values for calculating the constant came from as I thought that the calculation must be based on the numbers given in the chart?

19. In a photoelectric experiment, a student obtained the following data: Frequency of Radiation Maximum Kinetic Energy (x 1014 Hz) (x 10'19 J) 6.2 2.56 5.3 2.00 4.2 1.31 3.5 0.90 2.9 0.45 21) Draw a graph to show the relationship between the frequency of the incident radiation and the maximum kinetic energy of the electrons emitted from the photoelectric surface. b) Using only your graph, what is: i) the threshold frequency of the incident radiation? (Please include the error in your calculation.) 'Po 5 ' 9.00% 0\"sz Wf-l-V'o ii) Planck's constant? (Please include the error in your calculation.) 'l 1 "" 1| \" 1. - x i. (2.3 - 0-1)>Io"q3 $7,? ( S-'B - 2.4+)x [0'99]; m: = (3.2% '0'3'93'5