Help in testing of hyporthesis

Two tailed test  menas rejected region is represented by both sides..

E.g Statmement will belike this- There is No significant difference between population mean and Sample mean.

Right Tailed test: Population mean is greater than Sample mean

Left Tailed test: Population mean is less than Sample mean.

thanks pravin but i want ask is how to determine which alternative to use when?

K,See the following example

 The mean life time of sample of 400 light tubes produced by a Company is found to be 1570 hours with SD of 150 hours. Test the hypothesis whether the mean lifetime of the tubes produced by the company is greater than 1600 hours or not.

*( This is the problem in Padhukas Book page na 23.11 Q.no 2)

In this problem they have asked to verify whether sample mean (1570 with SD of 150 hrs) is Greater than or not of Population mean.

* Whenever Greater than is asked in Question it is Right tailed test.

* Whenever Smaller than is asked in question it is Left tail test.

If it was a two tailed test then question will be like this- Test the Hypothises whether there is any difference between Sample mean and Population mean.

( In two tail test only difference is asked it may be greater or smaller to population mean, so in either way it is difference)

The Above e.g is for analysis of two means (Sample and Popualtion), Same analogy will apply to Analysis of Variance and SD also.

I hope you understood.

Good Luck.

Thanks a lot... i have completely understood.. thanks a lot! Appreciated

thanks a lot..

sir but i have some doubt about the syllabus,

mr sanjay aggarwal have told us one 6 test

1 sample representing population = X(bar) - M(mu) *n/s.d.

sometime in the module they use n some time n-1 ..

i dont understand why this is done

and some other formula's as well when i saw the module there are so many other formula's as well can u tell me which are the formula's which are relevant for exam..

my email id is ankit_kulshrestha89 @ yahoo.co.in