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  • 1.  How to read the lower and upper bounds of 95% CI in BCa?

    Posted Mon November 02, 2020 10:04 AM

    I was carrying out a Pearson correlation with Bootstrapping and have issues understanding when to accept the p value and when not to depending on the 95% Bootstrapping confidence interval.

    I have read that if both the bounds are positive or negative, you can accept the conclusion that the p value gives. However, if one bound is positive and one negative, the conclusion given by the p value is wrong and you just need to negate that conclusion and accept the other one.

    I am unable to understand why do we negate when one is negative and one positive? How does that matter? Or is there something that I am missing?

    Also this rule of accepting and rejecting depending on the signs of the bounds, does it apply even when we bootstrap with T-test, ANOVA, etc.?






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  • 2.  RE: How to read the lower and upper bounds of 95% CI in BCa?

    Posted Mon November 02, 2020 02:52 PM

    This is no different from any other confidence interval. If the confidence interval contains zero, then the correlation is not significant, and the sig level will be large.






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  • 3.  RE: How to read the lower and upper bounds of 95% CI in BCa?

    Posted Mon November 02, 2020 04:24 PM

    So you mean to say, that if it contains a zero, we say that we accept the null hypothesis (they are same) in all case?

    Or do you mean that if it contains a zero, we negate what the p value told us.

    For example, p value is 0.06 which tells us that the 2 groups are same. However, the confidence intervals include a 0 between them.

    So in such a case, do we say that the conclusion that they are same is wrong, and we accept the alternate hypothesis that they are different.

    I just wish to know that if there is a 0 between the CI interval, we believe the opposite conclusion given by p value right?






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  • 4.  RE: How to read the lower and upper bounds of 95% CI in BCa?

    Posted Mon November 02, 2020 04:31 PM

    a p value tells you the probability of a difference that large or greater if the null hypothesis is true. A CI at a given confidence level tells you the range of differences under H0 that lie within that interval. It is not a statement that the p value is wrong.






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  • 5.  RE: How to read the lower and upper bounds of 95% CI in BCa?

    Posted Mon November 02, 2020 04:36 PM

    Okay I got it. But I am still confused as to how should I interpret the conclusion of the p value if there is a 0 between confidence interval.


    So I'll attach 2 references from where I get the doubt.


    https://methods.sagepub.com/dataset/howtoguide/bootstrapping-ehs-2009

    The link above shows an example and conclusion when both CI are positive.


    https://www.youtube.com/watch?v=P3T96y3wijg&ab_channel=how2stats

    The above video shows an example when there is a 0 in between and in this he concludes that the conclusion acc to the p value can be wrong. Hence, the actual conclusion is the opposite of what the p value gave






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