How do you know when to check normality or indepencence when constructing confidence intervals for proportions...

How do you know when to check normality or indepencence when constructing confidence intervals for proportions and means?

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Expert Solution

The normal condition:

While constructing confidence intervals for means, the sampling distribution of mean should be approximately normal. And a sample distribution can be approximate to its population if the sample size is sufficiently large such that

While constructing confidence intervals for proportions, the necessary condition for a sample distribution of proportion to be approximately normal is, . Where 'np' is the expected number of success in a sample which should be greater than equal to 10.

The independence condition:

While constructing confidence intervals for means, the standard error in the formula requires independence of the observations in the sample. And this condition holds if the sample size is 10% or less of the population (10% rule) when sampling is being done without replacement.

Similarly while constructing confidence intervals for proportions, the 10% rule condition should be follow.

orchestra answered 1 year ago

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