matlab 正态分布 求参数

用函数normfit

help normfit
NORMFIT Parameter estimates and confidence intervals for normal data.
[MUHAT,SIGMAHAT] = NORMFIT(X) returns estimates of the parameters of
the normal distribution given the data in X. MUHAT is an estimate of
the mean, and SIGMAHAT is an estimate of the standard deviation.

[MUHAT,SIGMAHAT,MUCI,SIGMACI] = NORMFIT(X) returns 95% confidence
intervals for the parameter estimates.

[MUHAT,SIGMAHAT,MUCI,SIGMACI] = NORMFIT(X,ALPHA) returns 100(1-ALPHA)
percent confidence intervals for the parameter estimates.