The world population, PPP (billion), is modelled by P=abtP = ab^tP=abt, where t t\,t is years since 1 April 1974. The linear relationship is log10P=0.008t+0.6\log_{10}P = 0.008t + 0.6log10P=0.008t+0.6.
a.[3]
Find, to 4 significant figures, the value of a a\,a and the value of bbb
b.[2]
With reference to the model interpret (i) the value of the constant aaa, (ii) the value of the constant bbb.
c.[2]
Find the world population, as predicted by the model, on 1 April 2020.
d.[1]
Given the world population on April 2020 was 7.8 billion use your answer in part (c) to comment on the suitability of the model.