PARAMETERS Subcommand (POWER ONEWAY ANOVA command)

PARAMETERS controls the test assumptions. The keywords specify the group sizes, the pooled population standard deviation, the group means, and the effect size.

POWER = value(s)

Optional keyword that specifies the desired power level(s). There is no default. Multiple values can be specified with each value separated by a blank space (or blank spaces). A grid of power values from value1 to value2 with the increment of value3, connected by the keywords TO and BY, can also be specified. When a grid of power values is specified, only one valid set of [value1 TO value2 BY value3] is allowed. Value1 and value2 must satisfy the condition 0 < value1 ≤ value2 < 1. The case where value1 = value2 is equivalent to specifying a single value1, regardless of value3. In order to restrict the number of power values, value3 must satisfy the condition 0.01 ≤ value3 < 1. The grid can be mixed with other power values, and can be placed anywhere.

Notes:

• All specified values must be in the range [0,1].
• In cases where duplicate values are specified, only unique values are used, and a warning message is generated to indicate that all duplicate values are excluded from the analysis.

SIGNIFICANCE = value

An optional keyword that specifies the significance level of the Type I error rate for the test. The value must be a single double value ∈(0,1). The default level is 0.05.

GROUP_SIZES = integers

A required keyword that specifies the group sizes. At least two integers are required. Each integer must be ≥ 2. Multiple integers are separated by a blank space (or blank spaces). The number of specified integers must be equal to that for GROUP_MEANS.

POOLED_SD = value

A required keyword that specifies the pooled population standard deviation. The value must be a single, numeric value > 0.

GROUP_MEANS = values

A required keyword that specifies the group means. At least two values are required. Multiple values are separated by a blank space (or blank spaces). The number of specified values must be equal to that for GROUP_SIZES.

ES = {F(value)} {ETA_SQUARED(value)}

An optional keyword that specifies the effect size of the overall test, which is measured by either f or η². When the keyword is specified, the following parameters and keywords are ignored:

• /PARAMETERS POOLED_SD
• /PARAMETERS GROUP_MEANS
• /CONTRAST PAIRWISE
• /CONTRAST ADJUST
• /PLOT POOLED_SD
• /PLOT TOTAL_N_XAXIS POOLED_SD_YAXIS
• /PLOT TOTAL_N_YAXIS POOLED_SD_XAXIS

Only a single numeric value is allowed in the parentheses following either F or ETA_SQUARED. When F is specified for ES, the specified value must be ≥ 0. When POWER is specified, the value cannot be 0. When ETA_SQUARED is specified for ES, the specified value must fall in the range 0 ≤ - <1. When POWER is specified, the value cannot be 0.

GROUP_WEIGHTS = values

A required keyword that assigns the group size weights when POWER is specified. The keyword takes effect when POWER is specified, and is ignored when GROUP_SIZES is specified. The default setting is EQUAL, which assigns the group weights all equal 1. The keyword can also be reset by specifying multiple values, separated by a blank space (or blank spaces). Each value must be ∈[1,100]. The number of specified values must be equal to that for GROUP_MEANS.

When /PARAMETER POWER and ES are specified simultaneously, a list of at least two values must clearly be specified to determine the number of groups, and EQUAL is no longer valid.