Confidence interval is the range of values around a sample statistic

In everyday terms, a confidence interval is the range of values around a sample statistic (such as mean
or proportion) within which clinicians can expect to get the same results if they repeat the study protocol
or intervention, including measuring the same outcomes the same ways. As you ask yourself, “Will I get
the same results if I use this research?”, you must address the precision of study findings, which is
determined by the Confidence Interval. If the CI around the sample statistic is narrow, you can be
confident you will get close to the same results if you implement the same research in your practice.
Consider the following example. Suppose that you did a systematic review of studies on the effect of tai
chi exercise on sleep quality, and you found that tai chi affected sleep quality in older people. If, according
to your study, you found the lower boundary of the CI to be .49, the study statistic to be 0.87, and the
upper boundary to be 1.25, this would mean that each end limit is 0.38 from the sample statistic, which is
a relatively narrow CI.
(UB + LB)/2 = Statistic [(1.25 + .49)/2 = .87]
Keep in mind that a mean difference of 0 indicates there is no difference; this CI does not contain 0.
Therefore, the sample statistic is statistically significant and unlikely to occur by chance.
Because this was a systematic review, and tai chi exercise has been established from the studies you
assessed as helping people sleep, based on the sample statistics and the CI, clinicians could now use
your study and confidently include tai chi exercises among possible recommendations for patients who
have difficulty sleeping.
Now you can apply your knowledge of CIs to create your own studies and make wise decisions about
whether to base your patient care on a particular research finding.
Initial Post Instructions
Find an example of a confidence interval in the news, scholarly source or medical journal. Summarize the
article/study. Does the article/study include the sample size and the level of confidence used to create the
confidence interval? Explain what the confidence interval means in context of the news article or scholarly
source.
Follow-Up Post Instructions
Respond to at least one peer. Further the dialogue by providing more information and clarification.
Here are some suggested responses
• How do you think the confidence interval that was presented in the study was calculated?
• Explain the mathematical concepts could you extract from this article/study.

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