It is always better if you can increase the sample size. But if you cannot do then there should not be any worry because t-test does not make any assumption of equality of sample size. But you should always test the equality of variance between the two groups. In case you found variance are differing you should either use Welch's correction to the degrees of freedom or should shift towards the Nonparametric test.
Madan Gopal Kundu
Indiana University Purdue University Indianapolis (IUPUI)
Indianapolis, Indiana 46202, USA
Sir Ronald Aylmer Fisher: "To call in the statistician after the experiment is done may be no more than asking him to perform a post-mortem examination: he may be able to say what the experiment died of."
Roger Brinner: "The plural of anecdote is not data."
John Tukey: "The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data."
--- On Sat, 14/11/09, Bilal <[log in to unmask]> wrote:
From: Bilal <[log in to unmask]>
Subject: Testing Differences between Groups
To: [log in to unmask]
Date: Saturday, 14 November, 2009, 5:41 PM
I have two groups named Middle Managers (MM) and Top Managers (TM) and I
want to test whether the mean differences between the two are significant or
My issue is that Group 1 (MM) has 150 respondents (10 respondents from one
organization each) while Group 2 (TM) has 15 respondents (One response from
each organization- Because Top Managers are fewer in numbers in a given
I plan to use T-test for testing the significance but am worried about the
disparity between sample size of the two groups...The data has already been
collected...Do I need to increase the sample size?
Would welcome any advice/suggestions in this regard...
Dr. Bilal Mustafa Khan
Department of Business Administration
Aligarh Muslim University (AMU)
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