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An estimate for the mean of a set of observations is just that - an estimate. Another set of observations will give a different estimates. These estimates for the mean will have a distribution which will have a standard error. If you have two sub-populations, the mean of each sub-population will have a standards error and the se of the difference between the means is a measure of the variability of the estimates of the difference.

A typical school work example: the heights of men and of women. There will be a mean height for men, Hm, with a se for men's heights and a mean height for women, Hw, with its own se. The difference in mean heights is Hm - Hw and which will have an estimated se.

Q: What does the standard error of the difference between means mean?

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Err means to go astray in thought or belief, error means a deviation from accuracy or correctness.

For the first part of your question: "http://wiki.answers.com/Q/What_three_elements_are_necessary_to_conduct_a_t-test_in_statistics_and_find_a_critical_value_and_test_for_a_scenario... This is a simple explanation, but a start. T-tests measure the difference between the means of 2 groups. The 2 groups should be of the same size. You take the difference between the means (a) and divide that by the Standard error of the difference between the means (b). a/b = t The Standard Error is the standard deviation divided by square root of the size of the population (n = number of things in the sample size). You need 2 standard errors because you have 2 populations. (To get the difference of the standard error, take the sum of the square of the standard deviation for each population, and divide the sum by n. Then take the square root of that calculation. That is the standard error of the difference of the mean. That goes into the denominator of the calculation from the 1st paragraph. FYI - variance = the square of the standard deviation.Once you've found t, you need to look it up in table. But you also need the degrees of freedom which is the sum of n for both groups, minus 2; and you need your confidence level, like at .05.

To reckon means to count. Its use as a synonym for "to think" in general is non-standard.

Labor cost variance means the difference between standard labor cost and actual labor cost.

It depends entirely on the variance (or standard error).

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Standard error of the mean (SEM) and standard deviation of the mean is the same thing. However, standard deviation is not the same as the SEM. To obtain SEM from the standard deviation, divide the standard deviation by the square root of the sample size.

Err means to go astray in thought or belief, error means a deviation from accuracy or correctness.

Err means to go astray in thought or belief, error means a deviation from accuracy or correctness.

For the first part of your question: "http://wiki.answers.com/Q/What_three_elements_are_necessary_to_conduct_a_t-test_in_statistics_and_find_a_critical_value_and_test_for_a_scenario... This is a simple explanation, but a start. T-tests measure the difference between the means of 2 groups. The 2 groups should be of the same size. You take the difference between the means (a) and divide that by the Standard error of the difference between the means (b). a/b = t The Standard Error is the standard deviation divided by square root of the size of the population (n = number of things in the sample size). You need 2 standard errors because you have 2 populations. (To get the difference of the standard error, take the sum of the square of the standard deviation for each population, and divide the sum by n. Then take the square root of that calculation. That is the standard error of the difference of the mean. That goes into the denominator of the calculation from the 1st paragraph. FYI - variance = the square of the standard deviation.Once you've found t, you need to look it up in table. But you also need the degrees of freedom which is the sum of n for both groups, minus 2; and you need your confidence level, like at .05.

Variance, standard deviation and standard error are the most common but there are also mean absolute error, standardised error range inter-quartile range The use of "error" does not mean that anything is wrong - the expression simply means difference from the expected value.

"Bug" means "error" in Computer Programming. So it means they're exactly the same.

HTTP 503 is the standard HTTP error that means "Service Unavailable."

An error in the logic of a program means that the output of the program is faulty (eg the program tell you 2+2=5). An error in semantics in a program means that the program statements are not constructed properly and the usual result of this is that the program will not compile.

Luxury means high standard quality including all specialities

To reckon means to count. Its use as a synonym for "to think" in general is non-standard.

If it's high that means it's very off and away from the actual value. If you find a low percent error it is very close or close to the true value.

Standard error A statistical measure of the dispersion of a set of values. The standard error provides an estimation of the extent to which the mean of a given set of scores drawn from a sample differs from the true mean score of the whole population. It should be applied only to interval-level measures. Standard deviation A measure of the dispersion of a set of data from its mean. The more spread apart the data is, the higher the deviation,is defined as follows: Standard error x sqrt(n) = Standard deviation Which means that Std Dev is bigger than Std err Also, Std Dev refers to a bigger sample, while Std err refers to a smaller sample