Precision Formula

Precision is implemented as follows:

To calculate precision from a base size (means)

Variables input:

The critical value, t, is calculated from a T-Table, based on the base size and desired alpha.

Compute the precision:

To calculate precision from a base size (proportions)

Variables input:

The critical value, z, is calculated from a Z-Table, based on the desired alpha.

Compute the precision:

To calculate base size for a target precision (means)

Variables input:

The critical value, t, is calculated from a T-Table, based on the base size and desired confidence level. This is implemented iteratively. For the first calculation, the "default" critical value is used prior to calculating the base size. After this base size is calculated for the first time, the formula is re-executing using the calculated critical value. This process is repeated until the same base size is returned twice in a row.

Compute the base size needed:

To calculate base size for a target precision (proportions)

Variables input:

The critical value, z, is calculated from a Z-Table, based on the desired confidence level.

Compute the base size needed: