plotting the probit model

I tried to plot the probit function as below.

I wrote a code which does not work. y above is equivalent to p below. t above is equivalent to z below. (please ignore i)

i
syms x p z a b
p=(1/sqrt(2*pi))*(int(exp(-(z^2)/2),z,-inf,a+b*x))
a=3.9833
b=0.04846
p=subs(p)
plot(x,p)

The result says that

    i
p = 
0.50000000000000003123668917430668*erf(0.034266394616300093032464917787601*x + 2.8166184415003747539458833475722) + 0.50000000000000003123668917430668 
Error using plot
Non-numeric data is not supported in 'Line'

I have not heard of 'erf', and I searched it.

Answer 1

[Star Strider]

Try this:

syms x p z a b
a = sym(3.9833);
b = sym(0.04846);
p = (1/sqrt(2*pi))*(int(exp(-(z^2)/2),z,-inf,a+b*x));

figure(1)
fplot(x,p, [-10 10])
grid

You can also use ezplot if you don’t have fplot, but with ezplot, you have to limit the y-axis with:

set(gca, 'Ylim',[0.9997  0.9999])

[Deokjae Jeong]

Thank you so much ! It works greatly.

[Star Strider]

My pleasure!