The formula for the confidence interval for a population proportion follows the same format as that for an estimate of a population mean. Remembering the sampling distribution for the proportion from Chapter 7, the standard deviation was found to be: Οp' = p(1 β p) nβ βββββββ Ο p' = p ( 1 β p) n. The confidence interval
Taking the exponent of the upper and lower confidence limits will give you the confidence interval for the risk ratio. RR = eln(RR) R R = e l n ( R R) You can convert the risk ratio into your original question of percent reduction (assuming the risk ratio is less than 1) with the following.
In Lesson 2 you first learned about the Empirical Rule which states that approximately 95% of observations on a normal distribution fall within two standard deviations of the mean. Thus, when constructing a 95% confidence interval we can use a multiplier of 2. meanβ2s meanβ1s mean+1s meanβ3s mean+3s mean mean+2s 68% 95% 99.7%.
This short video details how to construct a 90% confidence interval for a population mean when the population standard deviation has been given. In particula
The confidence interval indicates the level of uncertainty around the measure of effect (precision of the effect estimate) which in this case is expressed as an OR. Confidence intervals are used because a study recruits only a small sample of the overall population so by having an upper and lower confidence limit we can infer that the true
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how to find 98 confidence interval
