0
See the related links on how to calculate standard deviation. If there are more than a dozen data points, it is tedious to calculate by hand. Use excel or an online calculator. To get 2 standard deviations, multiply the calculated std deviation by 2.
Add your answer:
Earn +20 pts
What is the proportion of the total area under the normal curve within plus and minus two standard deviations of the mean?
95
What determines the standard deviation to be high?
Standard deviation is a measure of the scatter or dispersion of the data. Two sets of data can have the same mean, but different standard deviations. The dataset with the higher standard deviation will generally have values that are more scattered. We generally look at the standard deviation in relation to the mean. If the standard deviation is much smaller than the mean, we may consider that the data has low dipersion. If the standard deviation is much higher than the mean, it may indicate the dataset has high dispersion A second cause is an outlier, a value that is very different from the data. Sometimes it is a mistake. I will give you an example. Suppose I am measuring people's height, and I record all data in meters, except on height which I record in millimeters- 1000 times higher. This may cause an erroneous mean and standard deviation to be calculated.
What percent of a normal population is within 2 standard deviations of the mean?
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%
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
How would you write two billion in standard form?
Two billion in standard form is 2.0 × 109
How do you find two standard deviations above a mean?
It is mean + 2*standard deviation.
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.
I have two data sets with the same number of values with means x1 and x2 and standard deviations of n1 and n2. How do you average means with standard deviations?
You can't average means with standard deviations. What are you trying to do with the two sets of data?
What is the proportion of the total area under the normal curve within plus and minus two standard deviations of the mean?
95
Statistic question help?
When using Chebyshev's Theorem the minimum percentage of sample observations that will fall within two standard deviations of the mean will be __________ the percentage within two standard deviations if a normal distribution is assumed Empirical Rule smaller than greater than the same as
What is the measures that fall beyond three standard deviations of the mean called?
You may be referring to the statistical term 'outlier(s)'. Also, there is a rule in statistics called the '68-95-99 Rule'. It states that in a normally distributed dataset approximately 68% of the observations will be within plus/minus one standard deviation of the mean, 95% within plus/minus two standard deviations, and 99% within plus/minus three standard deviations. So if your data follow the classic bell-shaped curve, roughly 1% of the measures should fall beyond three standard deviations of the mean.
How do you multiply standard deviations?
Multiply them as you would any two numbers. However, you should note that the standard deviation of a product of two variables is not the product of their standard deviations. That is, SD(XY) ≠SD(X)*SD(Y)
What is the formula for finding numbers within two standard deviations of a mean?
The numbers must be greater than (mean - 2*sd) and laess than (mean + 2*sd).
When comparing two variances or standard deviations is an f-test is used?
An F-test can be used for variances.
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 is standard deviation useful?
It's used in determining how far from the standard (average) a certain item or data point happen to be. (Ie, one standard deviation; two standard deviations, etc.)
What is the approximate percentage score of less than 140 using the 68-95-99.7 rule if a set of test scores is normally distributed with a mean of 100 and a standard deviation of 20?
The 68-95-99.7 rule states that in a normally distributed set of data, approximately 68% of all observations lie within one standard deviation either side of the mean, 95% lie within two standard deviations and 99.7% lie within three standard deviations.Or looking at it cumulatively:0.15% of the data lie below the mean minus three standard deviations2.5% of the data lie below the mean minus two standard deviations16% of the data lie below the mean minus one standard deviation50 % of the data lie below the mean84 % of the data lie below the mean plus one standard deviation97.5% of the data lie below the mean plus two standard deviations99.85% of the data lie below the mean plus three standard deviationsA normally distributed set of data with mean 100 and standard deviation of 20 means that a score of 140 lies two standard deviations above the mean. Hence approximately 97.5% of all observations are less than 140.
