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TTestTwoInput

This node support 1-sample and 2-sample unpaired and paired t-tests.

The node requires that the data have an instance axis. For a one-sample t-test, the data in in the second input serves as the null-hypothesis value to compare against and must have either no instance axis, or only a since instance in its instance axis. For a two-sample unpaired t-test, the data in both inputs must have the same shape, except that they can have different numbers of instances. For a paired test, the packets must also have the same number of instances. Pairing assumes that the trials in both packets are ordered the same way. In the output packet, the instance axis will be replaced by a statistic axis (with label 'statistic_types'), which has fields for the t-value and the p-value. A feature axis with label 'explanatory_variables' will be added with with the element 'data1 vs data2'. (Note: For backward compatibility reasons (versions < 0.9.0), legacy_mode is set to True and therefore this node will store the stats in a Feature axis instead of a Statistic axis. Please update your pipelines as needed to assume a Statistic axis and then set legacy_mode to False. This will be deprecated in a future release.) More Info... Version 0.9.0

Ports/Properties

data

A packet containing at least one signal chunk with an instance axis.

  • verbose name: Data
  • default value: None
  • port type: DataPort
  • value type: Packet (can be None)
  • data direction: INOUT

data2

A packet containing signal chunks with names matching those in data. If matching chunks have an instance axis of length > 1 then a two-sample t-test is performed. If matching chunks do not have an instance axis or an instance axis of length==1, then a one sample t-test is performed and the values in data2 are used as a comparison value. Other than the instance axis, data2 will be repeated along axes with length==1 to match the shape of data.

  • verbose name: Data2
  • default value: None
  • port type: DataPort
  • value type: Packet (can be None)
  • data direction: IN

perform_paired_test

If True then a paired t-test comparing data and data2 is performed. If False (default), then an independent samples t-test is performed. Paired t-test requires that the length of data2 instance axis is the same as in data.

  • verbose name: Perform Paired Test
  • default value: False
  • port type: BoolPort
  • value type: bool (can be None)

nan_policy

Defines how to handle when input contains nan. ‘propagate’ returns nan, ‘raise’ throws an error, ‘omit’ performs the calculations ignoring nan values. Default is ‘propagate’.

  • verbose name: Nan Policy
  • default value: propagate
  • port type: EnumPort
  • value type: str (can be None)

equal_var

If True, perform a standard independent 2 sample test that assumes equal population variances. If False (default), perform Welch’s t-test, which does not assume equal population variance. This parameter is used only by 2 independent sample test.

  • verbose name: Equal Var
  • default value: False
  • port type: BoolPort
  • value type: bool (can be None)

legacy_mode

Store the statistics in a Feature axis instead of a Statistic axis. Included for backward compatibility and will be deprecated.

  • verbose name: Legacy Output Format
  • default value: True
  • port type: BoolPort
  • value type: bool (can be None)

use_caching

Enable caching.

  • verbose name: Use Caching
  • default value: False
  • port type: BoolPort
  • value type: bool (can be None)

set_breakpoint

Set a breakpoint on this node. If this is enabled, your debugger (if one is attached) will trigger a breakpoint.

  • verbose name: Set Breakpoint (Debug Only)
  • default value: False
  • port type: BoolPort
  • value type: bool (can be None)

metadata

User-definable meta-data associated with the node. Usually reserved for technical purposes.

  • verbose name: Metadata
  • default value: {}
  • port type: DictPort
  • value type: dict (can be None)