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How large a sample would be needed to have a standard error less than 2 points for population with a standard deviation of 20?
Wiki User
∙ 9y ago
A sample of size 100.
Wiki User
∙ 9y ago
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If a set of data has 100 points and a variance 4 then what is the standard deviation?
Standard deviation is the square root of the variance. Since you stated the variance is 4, the standard deviation is 2.
How do you calculate two standard deviations of the mean?
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.
What if you have a mean standardized score of 1500 points with a standard deviation of 150 points this data is normally distributed What is the z score of 1650?
The z score is (1650-1500)/150 = 150/150 = 1
Why is the standard deviation one?
The standard deviation provides in indication of what proportion of the entire distribution of the sample falls within a certain distance from the mean or average for that sample. If your data falls on a normal (or bell shaped) distribution, a SD of 1 indicates that about 68% of your data points (scores or whatever else) fall within 1 point (plus or minus) of the average (mean) of the data, and 95% fall within 2 points.
Can the variance be zero?
Variance is standard deviation squared. If standard deviation can be zero then the variance can obviously be zero because zero squared is still zero. The standard deviation is equal to the sum of the squares of each data point in your data set minus the mean, all that over n. The idea is that if all of your data points are the same then the mean will be the same as every data point. If the mean is the equal to every data point then the square of each point minus the mean would be zero. All of the squared values added up would still be zero. And zero divided by n is still zero. In this case the standard deviation would be zero. Short story short: if all of the points in a data set are equal than the variance will be zero. Yes the variance can be zero.
What is the minimum data required for standard deviation?
The standard deviation is a measure of how spread out the numbers are. Three points is needed to calculate a statistically valid meaningful standard deviation.
If a set of data has 100 points and a variance 4 then what is the standard deviation?
Standard deviation is the square root of the variance. Since you stated the variance is 4, the standard deviation is 2.
Is the standard deviation best thought of as the distance from the mean?
No. A small standard deviation with a large mean will yield points further from the mean than a large standard deviation of a small mean. Standard deviation is best thought of as spread or dispersion.
What is the standard deviation of the normal IQ curve?
It is 15 points.
If each score in a set of scores were increased by 6 points how would this affect the mean and the standard deviation?
This would increase the mean by 6 points but would not change the standard deviation.
What would it mean if a standard deviation was calculated to equal 0?
A standard deviation of zero means that all the data points are the same value.
What is a statistic inflection point?
There are two points of infection (the points where the curvature changes its direction) which lie at a distance of one standard deviation above mean and one standard deviation below mean.
In research how to define standard deviation?
Standard deviation shows how much variation there is from the "average" (mean). A low standard deviation indicates that the data points tend to be very close to the mean, whereas high standard deviation indicates that the data are spread out over a large range of values.
Can a standard deviation of 4.34 be correct?
Yes, a standard deviation of 4.34 can be correct. Standard deviation is a measure of dispersion or variability in a data set. It represents the average amount by which individual data points deviate from the mean. Therefore, a standard deviation of 4.34 simply indicates that there is some variability in the data, with data points on average deviating by 4.34 units from the mean.
Can standard deviation be above 10?
Yes, depending on the data being studied. Standard deviation can be thought of as the magnitude of the average distance between the data points and their mean.
What is the standard deviation if all data points are different?
It depends on the data. The standard deviation takes account of each value, therefore it is necessary to know the values to find the sd.
If a set of data has 100 points and variance 4 then the standard deviation is?
The SD is 2.
