School Commit Init

Anul 2/Semestrul 1/Probabilitati si statistica/test_2.m

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+X=[1001.7 975.0 978.3 988.3 978.7 988.9 1000.3 979.2 968.9 983.5 999.2 985.6];
+
+n=length(X);
+
+#oneminusalpha = input("Confidence level: (between 0 and 1)");
+oneminusalpha = 0.95;
+alpha = 1-oneminusalpha;
+
+#The null hypothesis is: H0: u=995 (it goes togheter with u>995, the standard is meet)
+#The alternative hypothesis is: H1: u<995 (the standard is not meet)
+#Left tail test for u when sigma is unknown
+
+printf("This is a left tail test for the mean when sigma is inknown\n\n");
+
+n0=995;
+
+[H, PVAL, CI, ZVALUE] = ttest(X,n0,'alpha',alpha,'tail','left');
+
+if H==1
+  printf("The null hypothesis is rejected\n\n");
+  printf("The data suggests that the standard is not meet\n\n");
+else
+  printf("The null hypothesis is not rejected\n\n");
+  printf("The data suggests that the standard is meet\n\n");
+endif
+
+oneminusalpha = 0.99;
+alpha = 1-oneminusalpha;
+
+v1=((n-1)*var(X))/(chi2inv(1-alpha/2, n-1));
+
+v2=((n-1)*var(X))/(chi2inv(alpha/2,n-1));
+
+s1=sqrt(v1);
+s2=sqrt(v2);
+
+printf("Confidence interval for the theoretical standard variance is (%4.3f, %4.3f)\n", s1,s2);