Change the color of one point on a plot

I'm trying to plot several data points on the same plot: a matrix of points, a regression line and a manual point. I would like to change the color of the manual point from the default color to black. The manual point is at 36 1. Everything in the code works and the manual point plots green. When I add the 'b' command to line 7 below, I get errors. Thanks for your help.

if true
z = sortrows(historicalDamage);
x = z(:,1);
y = z(:,2);
b = glmfit(x,y,'binomial','link','logit');
yfit = glmval(b,30:90,'logit');
subplot(2,1,2);
plot(x, y, 'o', 30:90, yfit, '-', 36, 1, 'o', 'b', 'LineWidth', 2);
title('Logistic Model Regression Curve')
xlabel('Ambient Temperature (°F)')
ylabel('Probability of Damage')
ylim([-0.5 1.5])
legend('Observed Failures', 'Logistic Model', 'Temp at Failied Launch (36 °F)');
end

Answer 1

[Walter Roberson]

plot(x, y, 'o', 30:90, yfit, '-', 36, 1, 'ok', 'LineWidth', 2);

[Bill Symolon]

That did it, thanks!