1. ## Help

My question is:

Find the critical value Chi squared R corresponding to a sample size of 3 and a confidence level of 95 percent.

I know that the critical value for 95% is 1.96. However, I'm stumped. I'm not sure with the above information what formula to use. Please help.

Thanks

2. 1NAMILL,

You can look up the critical value from the chi-square table, under row df=3-1=2 and column chi-square(0.95). If this is for a 95% confidence interval then you should get chi-square(2, 0.975).

1.96 is Z(0.975) from normal table, it's for a 95% confidence interval. Notice confidence interval is different from confidence level.

3. ## Thanks

Ok. I was thinking that the the confidence interval was the same as the confidence level.

Thanks,

4. Let me clarify. In a 95% confidence interval, your confidence level alpha=0.05, and your table value is Z(1-alpha/2)=Z(0.975) for normal random variables and chi-square(n-1, 0.975) for chi-square random variables, these are for the upper limits of the confidence intervals.

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