Wrinkles

How much variance is too much?

As a rule of thumb, a CV >= 1 indicates a relatively high variation, while a CV < 1 can be considered low. This means that distributions with a coefficient of variation higher than 1 are considered to be high variance whereas those with a CV lower than 1 are considered to be low-variance.26-Sept-2014

What variance is considered high?

The standard deviation of an exponential distribution is equal to its mean, so its coefficient of variation is equal to 1. Distributions with CV < 1 (such as an Erlang distribution) are considered low-variance, while those with CV > 1 (such as a hyper-exponential distribution) are considered high-variance.

How much difference in variance is acceptable?

Basically CV<10 is very good, 10-20 is good, 20-30 is acceptable, and CV>30 is not acceptable. Acceptance values depend on the variation in the sample matrix and the analytical method and are relative to the specification.

What is a bad variance?

Definition of Negative Variances on Accounting Reports Negative variances are the unfavorable differences between two amounts, such as: The amount by which actual revenues were less than the budgeted revenues.

Is it good to have a large variance?

Variance is neither good nor bad for investors in and of itself. However, high variance in a stock is associated with higher risk, along with a higher return. Low variance is associated with lower risk and a lower return. … Variance is a measurement of the degree of risk in an investment.

What is a good variance?

As a rule of thumb, a CV >= 1 indicates a relatively high variation, while a CV < 1 can be considered low. This means that distributions with a coefficient of variation higher than 1 are considered to be high variance whereas those with a CV lower than 1 are considered to be low-variance.

What is a good std deviation?

Statisticians have determined that values no greater than plus or minus 2 SD represent measurements that are more closely near the true value than those that fall in the area greater than ± 2SD. Thus, most QC programs call for action should data routinely fall outside of the ±2SD range.

What is a reasonable variance?

A variance of plus or minus 10% is generally agreed to be reasonable. Anything over 10% is considered a significant variance.