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# Hypothesis Testing (Correlation Test) (G Dataflow)

Tests hypotheses about the association between two populations x and y.  ## sample set x

Sampled data from population x. ## sample set y

Sampled data from population y. ## type

Type of correlation test to perform.

Name Description
Pearson Tests the Pearson correlation coefficient.
Spearman Tests the Spearman's rank correlation coefficient.
Kendall Tests the Kendall rank correlation coefficient.

Default: Pearson ## significance level

Probability that this node incorrectly rejects a true null hypothesis.

Default: 0.05 ## error in

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error  If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Default: No error ## alternative hypothesis

Hypothesis to accept if this node rejects the null hypothesis that populations x and y are uncorrelated.

Name Value Description
r != 0 0 The correlation coefficient between x and y is not equal to 0.
r > 0 1 The correlation coefficient between x and y is greater than 0.
r < 0 -1 The correlation coefficient between x and y is less than 0.

Default: r != 0 ## null hypothesis rejected?

A Boolean that indicates whether this node rejects the null hypothesis.

 True p value is less than or equal to significance level. This node rejects the null hypothesis and accepts the alternative hypothesis. False p value is greater than significance level. This node accepts the null hypothesis and rejects the alternative hypothesis. ## p value

Smallest significance level that leads to rejection of the null hypothesis based on the sample sets. ## confidence interval

Lower and upper limits for the correlation coefficient of the two populations. confidence interval indicates the uncertainty in the estimate of the true correlation coefficient. ### low

Lower limit of the estimate of the correlation coefficient of the two populations. ### high

Upper limit of the estimate of the correlation coefficient of the two populations. ## correlation test information

Sample statistics of the correlation test. ### correlation coefficient r

Linear correlation coefficient between x and y. ### r critical value

r critical value that corresponds to significance level and alternative hypothesis.

Algorithm for Calculating r critical value

Let X represent a random variable that follows the distribution of the test statistics. r critical value satisfies the following equations based on the value of alternative hypothesis.

alternative hypothesis r critical value
r != 0 Prob{X > r critical value} = significance level / 2
r > 0 Prob{X > r critical value} = significance level
r < 0 Prob{X > r critical value} = significance level ## error out

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error  If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported

Web Server: Not supported in VIs that run in a web application