Explain the absolute temperature on the celsius scale

Question

For these data calculate the best value for the absolute temperature on the Celsius scale.

Charles's law is sometimes expressed in the form V₀ (1+αθ), where θ is the Celsius temperature, α, is the constant, and V₀ is the volume of the sample at 0^oC. The following values for have been reported for nitrogen at 0^oC.

P/Torr            749.7      599.6      333.1      98.6

10³α/ (^oC)^-1   3.6717   3.6697   3.6665   3.6643