Physics - pendulum?

Question

For a certain pendulum, periods of T = .708, .8943636, 1.02536 and 1.129783 seconds are observed for respective lengths L = 4, 8, 12 and 16 units.
•Determine whether the transformation T -> T2 or T -> T3 linearizes the function better.

Answer 1

We know that
T=2 pi sqrt (L/g)
since you are dealing with units rather then say meter or feet use
T=2 pi sqrt(kL/g)
T- period in sec
pi= 3.14159...
k - proportionality constant
L - length of the pendulum (from point of suspension to the center of the mass)

Compute values for each case and compare by how much they deviate from the experimental values given. Use the slopes like

m1=(L2-L1)/(T2-T1)


What are the transformation?