|
Size: 784
Comment:
|
Size: 820
Comment:
|
| Deletions are marked like this. | Additions are marked like this. |
| Line 3: | Line 3: |
| If two 95% confidence intervals overlap this does ''not'' imply that the two statistics on whicb they are based (e.g. means, odds ratios) differ at the 5 percent level. In other words it is possible for the difference between two statistics to be statistically non-zero and for their respective confidence intervals still to overlap. This is usually the case when the difference between the means has moderate significance. | If two 95% confidence intervals overlap this does ''not'' imply that the two statistics on which they are based (e.g. means, odds ratios) differ at the 5 percent level. In other words it is possible for the difference between two statistics to be statistically non-zero and for their respective confidence intervals still to overlap. This is usually the case when the difference between the means has moderate significance. |
| Line 7: | Line 7: |
| The rationale behind the above discrepancy is explained in this [attachment:cis.pdf article] taken from the Cornell University website. | The rationale behind the above discrepancy is explained in this [attachment:cis.pdf article] taken from the Cornell University website. See also [attachment:cis2.pdf here.] |
A note on confidence intervals and statistical significance
If two 95% confidence intervals overlap this does not imply that the two statistics on which they are based (e.g. means, odds ratios) differ at the 5 percent level. In other words it is possible for the difference between two statistics to be statistically non-zero and for their respective confidence intervals still to overlap. This is usually the case when the difference between the means has moderate significance.
It is true, however, that if a pair of confidence intervals do not overlap the difference between the two statistics is statistically non-zero.
The rationale behind the above discrepancy is explained in this [attachment:cis.pdf article] taken from the Cornell University website. See also [attachment:cis2.pdf here.]