Q23 of Notes

Discussion in 'CA3' started by Snowy, Apr 27, 2009.

  1. Snowy

    Snowy Member

    Hypothesis testing:
    Why is the result of 94% or over very UNlikely at 90% confidence interval?
     
  2. Margaret Wood

    Margaret Wood Member

    In Q23, you are testing the null hypothesis that 90% of customers are happy with your service (ie p=0.9) against the alternative hypothesis that more than 90% are happy with your service (ie p>0.9).

    In your sample of 100 customers, 94 were happy with your service, ie the sample proportion is 0.94. We want to know if this is significant at the 10% level.

    This result will be significant at the 10% level if the probability of getting a sample result as high as this when the true proportion is actually 0.9, is less than 10%. In this case the probability is less than 10%, so the result is significant. It suggests that more than 90% are happy with your service.
     

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