Here is the data about the population (in thousands) of Houston vs years since 1990.

data={{0,184},{10,236},{20,332},{30,528},{40,737},{50,1070},
{60,1583},{70,2183},{80,3122},{90,3733},{100,4672},{110,5937}};
N[Correlation[data][[1]][[2]]]
dataplot=ListPlot[data,PlotStyle->PointSize[0.015]];

Fit the data to a line

lm=LinearModelFit[data,x,x]
lm["EstimatedVariance"]
modelplot=Plot[lm[t],{t,0,110},PlotStyle->Red];
Show[dataplot,modelplot,PlotLabel->Style["Houston Population",15],Frame->True,FrameLabel->{"Years since 1990","Population (thousands)"},FrameStyle->15]

Fit the data to a quadratic function

qm=NonlinearModelFit[data,a x^2+b x + c, {a,b,c},x]
qm["EstimatedVariance"]
modelplot=Plot[qm[t],{t,0,110},PlotStyle->Red];
Show[dataplot,modelplot,PlotLabel->Style["Houston Population",15],Frame->True,FrameLabel->{"Years since 1990","Population (thousands)"},FrameStyle->15]

Fit the data to an exponential function

em=NonlinearModelFit[data,a b^x, {a,b},x]
em["EstimatedVariance"]
modelplot=Plot[em[t],{t,0,110},PlotStyle->Red];
bookplot=Plot[190 (1.034)^t,{t,0,110},PlotStyle->Blue];
Show[dataplot,modelplot,bookplot,PlotLabel->Style["Houston Population",15],Frame->True,FrameLabel->{"Years since 1990","Population (thousands)"},FrameStyle->15]