例6-79  正態(tài)分布的參數(shù)估計(jì)。
有3組(每組40個(gè)元素)正態(tài)隨機(jī)數(shù)據(jù)，其均值為25，均方差為3，求95%的置信區(qū)間和參數(shù)估計(jì)值。
>> X = normrnd (25,3,40,3)
X =
   25.6883   24.0916   27.4359
   21.2773   23.2913   24.5716
   27.1000   24.6355   24.7004
   26.2806   23.8295   22.5996
   29.3644   22.4671   26.4797
   23.4694   19.7867   28.7127
   24.9800   23.6514   28.8879
   23.4235   20.3562   24.1654
   27.1531   24.7127   25.6514
   28.2651   27.7231   26.8922
   26.5017   32.1088   23.3544
   33.3154   26.5593   25.6889
   24.5191   26.2316   26.0659
   26.2885   28.1578   26.5639
 ……
>> [mu,sigma,muci,sigmaci] = normfit(X)
mu =
   24.7266   25.0217   25.6256
sigma =
    3.1334    3.0349    3.1109
muci =
   23.7245   24.0511   24.6307
   25.7287   25.9923   26.6205
sigmaci =
    2.5667    2.4861    2.5484
    4.0233    3.8970    3.9945
>>