to view the statistics calculation options.
Choose the Stat option from the main menu.
Press
to view the statistics calculation options.
to select one-variable statistics. to select two-variable statistics.
to set the statistical settings. 
to view regressions. 
to select
linear regression which finds the best-fit
linear equation of the form y = ax + b. to select
med-med regression which finds another best-fit
linear equation of the form y = ax + b. to select
quadratic regression which finds the best-fit
quadratic equation of the form y = ax2 + bx + c.
to select
cubic regression which finds the best-fit
cubic equation of the form y = ax3 + bx2 + cx + d.
to select
quartic regression which finds the best-fit
quartic equation of the form y = ax4 + bx3 + cx2 + dx + e. to select
logarithmic regression which finds the best-fit
logarithmic equation of the form y = a + b ln x. to select
exponential regression which finds the best-fit
exponential equation of the form y = aebx. to select
power regression which finds the best-fit
power equation of the form y = axb. to select
sinusoidal regression which attempts to finds an approximating equation of the form
y = a sin(bx+c) + d. to select
logistic regression which attempts to finds an approximating equation of the form
y = c / (1 + ae-bx).