Dear Stata user/Professional!
I have a problem of integral function estimation for the Normal, Beta, Gamma, and Weibull density function in stata.
I am using rice yield data for 21 years i.e.2531,2783,2849, 2852,2947,2999,3020,3033,3077,3082,3093,3098,3176,3182,3197,
3229,3242,3247,3276,3307,and 3521. The mean and stdev are 3083 ans 214.
I tried as stata command explained in manual. For Normal distribution, I applied following command:

x=yield
gen y=exp((-.5*(x-3083)^2)/214^2)/((2*3.1416)^(1/2)*214)
dydx y x, gen(yprime)
integ y x, gen(Sy)trapezoid

results:
number of points = 21
integral = 1.005708

The result 1.005708 is fine for yield 0 to 3521

Now, I want to estimate integral (probability)value of yields less than 2620. I could not find the way how to give command to estimate integral (probability)value of yields less than 2620.

I need a suggestion to solve this problem.
Any kind of suggestion is highly appreciated.
Thank you.
Kind regards