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What percent of a normal population is within 2 standard deviations of the mean?
Wiki User
∙ 14y ago
By the definition of standard deviation, 95.46% of the normal population will be within 2 SD of the mean.
Explanation: The normal distribution of a population means it follows the "bell curve". The center of this bell curve is the population's mean value. One standard deviation defines two areas (on the left and right side of the central "mean" value) under the bell curve that each have 34.13% of the population. The next standard deviation adds two additional areas under the curve, each having 13.6% of the population. Adding the areas under the curves on both sides gives us (34.13% + 13.6%) x 2 = 95.46%
Wiki User
∙ 14y ago
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If a data point has a corresponding score of -1.5 then it is one and a half standard deviations above the mean value.?
If you are talking about the z-value of a point on the normal curve, then no, it is 1.5 standard deviations BELOW the mean.
What is the proportion of the total area under the normal curve within plus or minus 2 standard deviations?
95%
What percent of data falls between 1 Standard deviation below and 2 stand deviations above the mean?
The answer will depend on what the distribution is. Non-statisticians often assum that the variable that they are interested in follows the Standard Normal distribution. This assumption must be justified. If that is the case then the answer is 81.9%
What is the proportion of the total area under the normal curve within plus and minus two standard deviations of the mean?
95
What is the formula to determine the standard deviation of the resulting normal distribution when adding two normal distributions with different means and standard deviations?
s= bracket n over sigma i (xi-x-)^2 all over n-1 closed bracket ^ 1/2
In a standard normal distribution 95 percent of the data is within plus standard deviations of the mean?
95% is within 2 standard deviations of the mean.
How many standard deviations are 95 percent of measurements away from the mean?
95 percent of measurements are less than 2 standard deviations away from the mean, assuming a normal distribution.
What percent of the data in a normal distribution lies more than 2 standard deviations above the mean?
2.275 %
What does normality mean in health and social care?
All minor deviations occurring with two standard deviations under the Gaussian curve are considered normal. Deviations occurring outside of two standard deviations are considered abnormal.
How many standard deviations is needed to capture 75 percent of data?
It depends on the shape of the distribution. For standard normal distribution, a two tailed range would be from -1.15 sd to + 1.15 sd.
According to the normal probability distribution 95 percent of the values of a normal random variable are contained w in plus or minus how many standard deviations from the mean Why is that important?
Approximately 2 standard deviations (1.96, actually) from the mean. That is important to know that if one has a sample of 1000 values, if one selects a threshold at +/- 2 standard deviations from the mean, then one expects to see about 25 values exceeding those thresholds (on each side of the mean)
What percentage of scores fall within -3 and plus 3 standard deviations around the mean in a normal distribution?
99.7% of scores fall within -3 and plus 3 standard deviations around the mean in a normal distribution.
In statistics what does the empirical rule states?
Nearly all the values in a sample from a normal population will lie within three standard deviations of the mean. Please see the link.
What percentage of a normal distribution is within 2 standard deviations of the mean?
I believe the standard deviations are measured from the median, not the mean.1 Standard Deviation is 34% each side of median, so that is 68% total.2 Standard Deviations is 48% each side of median, so that is 96% total.
If average height for women is normally distributed with a mean of 65 inches and a standard deviation of 2.5 inches then approximately 95 percent of all women should be between what and what inches?
A normal distribution with a mean of 65 and a standard deviation of 2.5 would have 95% of the population being between 60 and 70, i.e. +/- two standard deviations.
The mean plus or minus the standard deviation for a normal distribution provides a probability range of what percent?
in a normal distribution, the mean plus or minus one standard deviation covers 68.2% of the data. If you use two standard deviations, then you will cover approx. 95.5%, and three will earn you 99.7% coverage
How many standard deviations is the first quartile away from the mean on a Normal distribution?
0.674 sd.
