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What happens to the confidence interval as the standard deviation of a distribution increases?
Courtcase
The standard deviation is used in the numerator of the margin of error calculation. As the standard deviation increases, the margin of error increases; therefore the confidence interval width increases. So, the confidence interval gets wider.
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∙ 14y ago
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The width of a confidence interval is equal to twice the value of the margin of error?
No. The width of the confidence interval depends on the confidence level. The width of the confidence interval increases as the degree of confidence demanded from the statistical test increases.
If the standard deviation is doubled what will be the effect on the confidence interval?
The confidence intervals will increase. How much it will increase depends on whether the underlying probability model is additive or multiplicative.
When comparing the 95 percent confidence and prediction intervals for a given regression analysis what is the relation between confidence and prediction interval?
Confidence interval considers the entire data series to fix the band width with mean and standard deviation considers the present data where as prediction interval is for independent value and for future values.
What percentage is 1.5 standard deviation?
The interval of 1.5 sd either side of the mean contains 87 of the values of a Gaussian distribution. For other distribution the answers will be different.
When do you know when to use t-distribution opposed to the z-distribution?
z- statistics is applied under two conditions: 1. when the population standard deviation is known. 2. when the sample size is large. In the absence of the parameter sigma when we use its estimate s, the distribution of z remains no longer normal but changes to t distribution. this modification depends on the degrees of freedom available for the estimation of sigma or standard deviation. hope this will help u.... mona upreti.. :)
What happens to the confidence interval as the standard deviation of a distribution decreases?
It goes up.
If the variance of a distribution increases will the confidence in a given interval decrease?
Yes.
When population distribution is right skewed is the interval still valid?
You probably mean the confidence interval. When you construct a confidence interval it has a percentage coverage that is based on assumptions about the population distribution. If the population distribution is skewed there is reason to believe that (a) the statistics upon which the interval are based (namely the mean and standard deviation) might well be biased, and (b) the confidence interval will not accurately cover the population value as accurately or symmetrically as expected.
The width of a confidence interval is equal to twice the value of the margin of error?
No. The width of the confidence interval depends on the confidence level. The width of the confidence interval increases as the degree of confidence demanded from the statistical test increases.
Is it true that the larger the standard deviation the wider the confidence interval?
no
What happen to confidence interval if increase sample size and population standard deviation simultanesous?
The increase in sample size will reduce the confidence interval. The increase in standard deviation will increase the confidence interval. The confidence interval is not based on a linear function so the overall effect will require some calculations based on the levels before and after these changes. It would depend on the relative rates at which the change in sample size and change in standard deviation occurred. If the sample size increased more quickly than then standard deviation, in some sense, then the size of the confidence interval would decrease. Conversely, if the standard deviation increased more quickly than the sample size, in some sense, then the size of the confidence interval would increase.
What happens to the width of the confidence interval when you are unable to get a large sample size?
The width of the confidence interval increases.
What happens to interval when level of confidence is increased?
it increases
What happens to the confidence interval as the sample estimate increases?
Assuming that other measures remain the same, as the sample estimate increases both ends of the confidence interval will increase. In effect, the confidence interval will be translated to a higher value without any change in its size.Assuming that other measures remain the same, as the sample estimate increases both ends of the confidence interval will increase. In effect, the confidence interval will be translated to a higher value without any change in its size.Assuming that other measures remain the same, as the sample estimate increases both ends of the confidence interval will increase. In effect, the confidence interval will be translated to a higher value without any change in its size.Assuming that other measures remain the same, as the sample estimate increases both ends of the confidence interval will increase. In effect, the confidence interval will be translated to a higher value without any change in its size.
What effect increasing only the population standard deviation will have on the width of the confidence interval?
It will make it wider.
When the sample size and sample standard deviation remain the same a 99 percent confidence interval for a population mean will be narrower than the 95 percent confidence interval for the mean?
Never!
How do you calculate confidence interval?
Confidence intervals may be calculated for any statistics, but the most common statistics for which CI's are computed are mean, proportion and standard deviation. I have include a link, which contains a worked out example for the confidence interval of a mean.
