PARAMETERS Subcommand (POWER MEANS RELATED command)

PARAMETERS controls the test assumptions. The keywords specify the number of group pairs, the population standard deviation(s), the Pearson product-moment correlation co-efficient ρ, the population mean(s) under testing, 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.

TEST = {NONDIRECTIONAL}{DIRECTIONAL}

An optional keyword that determines whether the test is one or two-sided. NONDIRECTIONAL, or a two-sided test, is the default setting. When DIRECTIONAL is specified, power is computed for a one-sided test.

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.

NPAIRS = integer

A required keyword that specifies the number of group pairs. The value must be a single integer > 1. NPAIRS and POWER cannot be specified simultaneously.

SD = {value} {value1 value2}

A required keyword that specifies the population standard deviation(s). Note that value, value1, and value2 are all numeric values > 0. Multiple parameters value1 and value2, if specified, are separated by a blank space (or blank spaces). When a single value is specified, it denotes the population standard deviation of the group difference σ_d. When two values (value1 and value2) are specified, they denote σ₁ and σ₂, respectively.

RHO = value

An optional keyword that specifies the Pearson product-moment correlation coefficient ρ. The value must be a single numeric ∈[−1,1] and cannot be 0. The default value is 0.5. Note that this keyword is ignored when a single value is specified for SD. Otherwise, when two values (value1 and value2) are specified for SD, this keyword takes effect and is used to compute σ_d. In cases where value1=value2 is specified for SD, ρ=1 is not allowed.

MEAN = {value} {value1 value2}

A required keyword that specifies the population mean(s) under testing. Note that value, value1, and value2 are all numeric values. Multiple parameters value1 and value2, if specified, are separated by a blank space (or blank spaces). When a single value is specified, it denotes the population mean difference μ_d. When two values(value1 and value2) are specified, they denote μ₁ and μ₂, respectively.

ES = value

An optional keyword specifies the effect size as an input to the estimation of the power or sample size. Must be a single numeric value. When /PARAMETERS TEST = NONDIRECTIONAL, the specified value must be ≥ 0, when POWER is specified, the specified value cannot be 0.

Note: ES cannot be specified together with SD, RHO, or MEAN.