Hypothesis Test for Balanced Load on 6 I/O Channels - N = 150

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Discussion Overview

The discussion revolves around testing the hypothesis that the load on six I/O channels in a computer system is balanced, based on observed data from 150 I/O operations. Participants explore the application of the chi-square test for this hypothesis.

Discussion Character

  • Technical explanation, Debate/contested, Mathematical reasoning

Main Points Raised

  • One participant proposes using the chi-square statistic \(\chi^2 = (O-E)^2 / E\) to test the hypothesis of balanced load.
  • Another participant confirms the use of the chi-square test and inquires about how to calculate the expected values (E).
  • A participant suggests that the expected value (E) can be calculated as the total number of operations divided by the number of channels, specifically \(E = \Sigma x_i / 6\).
  • It is noted by another participant that if each I/O operation is assumed to be equally probable, then \(E\) would equal \(150/6 = 25\).
  • One participant expresses gratitude for the confirmation of their calculation.
  • A later reply questions the sincerity of the previous participant's request for confirmation, suggesting possible sarcasm.

Areas of Agreement / Disagreement

Participants generally agree on the use of the chi-square test and the method for calculating expected values, but there is a hint of disagreement regarding the tone and intent behind the confirmation request.

Contextual Notes

There is an implicit assumption that the I/O operations are uniformly distributed, but this is not explicitly confirmed by all participants. The discussion does not resolve whether the initial hypothesis is valid or the appropriateness of the chi-square test in this context.

TomJerry
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Question : A computer system has 6 I/O channels and the system personnel are reasonably certain that the load on channels is balanced. If X is random variable denoting the index of the channel to which a given I/O operations is directed , that its pmf is assumed to be uniformly distributed. Out of N=150 I/O operation onserved, the number of operations directed to various channels were:
n0 = 22 ; n1 = 23 ; n2 = 29 ; n3 = 31 ; n4 = 26 ; n5 = 19

Test the hypothesis that the load on channels is balanced at 5 percent level of significance.

Solution
I have used the [tex]\chi[/tex]2 = (O-E)2 / E

where O - obsevred and E is expected

Is this correct or should i be using some other method
 
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TomJerry said:
Question :

where O - obsevred and E is expected

Is this correct or should i be using some other method

You can use the chi square test [tex]\chi^2=\sum (O-E)^2/E[/tex] Do you know how to get E?
 
Last edited:
SW VandeCarr said:
You can use the chi square test [tex]\chi^2=\sum (O-E)^2/E[/tex] Do you know how to get E?

I have taken all the E = [tex]\Sigma[/tex]xi/6

Is that correct?
 
TomJerry said:
I have taken all the E = [tex]\Sigma[/tex]xi/6

Is that correct?

Yes. If each I/O is taken as equally probable, 150/6=25=E.
 
SW VandeCarr said:
Yes. If each I/O is taken as equally probable, 150/6=25=E.

Thanks
 
If you're being sarcastic, why did you ask for confirmation in the first place?
 
Last edited:

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