Calculate grand average and individual mean amplitudes and standard deviations

Description

m.measures calculates mean amplitude and standard deviation for each condition in the data frame, for the specified time window. Values are calculated based on grand average waveforms, as well as for each individual subject. Values are based on the electrode, or electrode cluster for dense arrays, provided in electrodes.

Usage

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m.measures(data, electrodes, window)

Arguments

data

A data frame in the format returned from load.data

electrodes

A single value or concatenation of several values (to be averaged) indicating which electrodes to include in generating the plot. At this time, if the raw data files imported using load.data) do not have a header, you must include a capital "V" in front of the number and enclose each electrode in quotes. (For example, electrodes = "V78", or electrodes = c("V78", "V76").)

window

The beginning and end points of a time window of interest; this is different from the beginning and ending times epoch.st and epoch.end defined in load.data (you only need to define the epoch once upon importing the data).

Details

Single electrodes can be passed to the package functions, or several electrodes can be provided (i.e., when using dense arrays) and those electrodes will be averaged together as a single electrode.

Value

A data frame with columns labeled:

  • Subject

  • Trial Type

  • Standard Deviation

  • Mean Amplitude

Author(s)

Travis Moore

Examples

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# Calculate mean amplitude and standard deviation
m.measures(ERPdata, electrodes = "V78", window = c(1000, 1500))