Data - Preprocess Responses
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To use Preprocess Responses, you must create or define a 2-level factorial design and enter response data that includes at least one of following:

·    Repeat responses

·    Replicate responses

·    Precalculated standard deviations for your repeat or replicate responses

Each row in your worksheet contains data corresponding to one run of your experiment. You enter repeat and replicate responses differently from each other following the examples below. You can have both repeat and replicate measurements for the same response. Response columns must be equal in length to the design variables in the worksheet. Enter data in any columns not occupied by the design data.

Repeats

Enter up to 200 repeats for one response in numeric columns, one column for each repeated measurement. You must have at least two repeats at each run for Minitab to calculate a standard deviation. Each run need not have the same number of repeats. In this case, you must type the missing value symbol "*" in the empty cells (see the example below). Enter your data following this example:

Replicates

Enter your replicate observations for a response in one column, in the row corresponding to the appropriate run of the experiment. You can calculate standard deviations for up to 10 different responses at a time. You need not have the same number of replicates for each combination of factor settings, but you must have at least two at each run for Minitab to calculate a standard deviation. Enter your data following this example:

Precalculated standard deviations

Enter your precalculated standard deviations, one column for each response, in the row corresponding to the appropriate run. You can store up to 10 columns of standard deviations at a time. You must enter a column or a constant indicating the number of repeats or replicates in your experiment.

For replicates, enter the standard deviation in the row where each combination of factor settings first appears. Minitab enters missing values in the empty cells. Because the columns must be equal in length to the design variables in the worksheet, you may need to enter a missing value in the last row to make the column length correct.

Covariates

Enter covariates in columns equal in length to the design variables in the worksheet in the row corresponding to the appropriate run. Minitab can adjust replicate standard deviations for up to 50 covariates.

Analyzing design with botched runs

A botched run occurs when the actual value of a factor setting differs from the planned factor setting. When a botched run occurs, you need to change the factor levels for that run in the worksheet. If you have botched runs for replicates of the same combination of factor settings, Minitab does not recognize them as replicates. You must have two or more replicates at the same combination of factor settings to compute a standard deviation.