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How do you find percentiles when given standard deviation and mean?
Wiki User
∙ 12y ago
Each standard deviation represents a certain percentile. So if we use two decimal places, −3 is the 0.13th percentile, −2 the 2.28th percentile, −1 the 15.87th percentile, 0 the 50th percentile , +1 the 84.13th percentile, +2 the 97.72th percentile, and +3 the 99.87th percentile.
The mean, median and mode are all the same it the distribution is normal.
BUT WHY DOES THIS WORK? HOW DO YOU DO IT?
The main idea to make all this work and understandable is that the area under the normal curve is one. So if you have a SD and a mean, you can find the z score.
Then, using a calculator, or a table, or even sometimes just some rules you may have learned like the empirical rule, you can find the area to the left or right of any given z score. This area is actually a percentile!
So for example, if convert a data point to a z - score using the mean and standard deviation ( The formula is z=(x-mean)/standard deviation, by the way), and I look up the probability of that z-score, and say it is .25. Then it is the 25th percentile.
The table below gives you all the percentiles and their corresponding z scores.
z-score percentile for normal distribution
Percentilez-ScorePercentilez-ScorePercentilez-Score1-2.32634-0.412670.442-2.05435-0.385680.4683-1.88136-0.358690.4964-1.75137-0.332700.5245-1.64538-0.305710.5536-1.55539-0.279720.5837-1.47640-0.253730.6138-1.40541-0.228740.6439-1.34142-0.202750.67410-1.28243-0.176760.70611-1.22744-0.151770.73912-1.17545-0.126780.77213-1.12646-0.1790.80614-1.0847-0.075800.84215-1.03648-0.05810.87816-0.99449-0.025820.91517-0.954500830.95418-0.915510.025840.99419-0.878520.05851.03620-0.842530.075861.0821-0.806540.1871.12622-0.772550.126881.17523-0.739560.151891.22724-0.706570.176901.28225-0.674580.202911.34126-0.643590.228921.40527-0.613600.253931.47628-0.583610.279941.55529-0.553620.305951.64530-0.524630.332961.75131-0.496640.358971.88132-0.468650.385982.05433-0.44660.412992.326
Wiki User
∙ 12y ago
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How do you find highest standard deviation in given number?
Standard deviations are measures of data distributions. Therefore, a single number cannot have meaningful standard deviation.
How do you find the sample size when given the standard deviation and the mean with a sample value?
You cannot from the information provided.
How do i find sample standard deviation from population standard deviation?
If the population standard deviation is sigma, then the estimate for the sample standard error for a sample of size n, is s = sigma*sqrt[n/(n-1)]
How do you find the standard deviation for data?
Standard deviation calculation is somewhat difficult.Please refer to the site below for more info
Find the standard deviation for 44 46 33 10 50 27?
The deviation is 1694.
How do you find highest standard deviation in given number?
Standard deviations are measures of data distributions. Therefore, a single number cannot have meaningful standard deviation.
If quartile deviation is 24. find mean deviation and standard deviation?
Information is not sufficient to find mean deviation and standard deviation.
Why would someone need a standard deviation calculator?
A standard deviation calculator allows the user to find the mean spread away from the mean in a statistical environment. Most users needing to find the standard deviation are in the statistics field. Usually, the data set will be given and must be typed into the calculator. The standard deviation calculator will then give the standard deviation of the data. In order to find the variance of the data, simply square the answer.
How do you find the sample size when given the standard deviation and the mean with a sample value?
You cannot from the information provided.
Why we calculate standard deviation and quartile deviation?
we calculate standard deviation to find the avg of the difference of all values from mean.,
Is variance the square root of standard deviation?
No, you have it backwards, the standard deviation is the square root of the variance, so the variance is the standard deviation squared. Usually you find the variance first, as it is the average sum of squares of the distribution, and then find the standard deviation by squaring it.
How do solve the frequency distribution?
The answer will depend on what you mean by "solve". Find the mean, median, mode, variance, standard error, standard deviation, quartiles, deciles, percentiles, cumulative distribution, goodness of fit to some distribution etc. The question needs to be a bit more specific than "solve".
How do you find the sample deviation?
You're an idiot. It's standard deviation. Google that for your answer.
How do you find graph median by using standard deviation?
You cannot because the median of a distribution is not related to its standard deviation.
How do i find sample standard deviation from population standard deviation?
If the population standard deviation is sigma, then the estimate for the sample standard error for a sample of size n, is s = sigma*sqrt[n/(n-1)]
Give an example of how to find the standard deviation?
Look at the Wikipedia article on "Standard deviation" - it includes an example right at the beginning.
How do you find the standard deviation for data?
Standard deviation calculation is somewhat difficult.Please refer to the site below for more info
