# delta.ind.t: d-delta for Between Subjects with Control Group SD... In MOTE: Effect Size and Confidence Interval Calculator

## Description

This function displays d-delta for between subjects data and the non-central confidence interval using the control group standard deviation as the denominator.

## Usage

 `1` ```delta.ind.t(m1, m2, sd1, sd2, n1, n2, a = 0.05) ```

## Arguments

 `m1` mean from control group `m2` mean from experimental group `sd1` standard deviation from control group `sd2` standard deviation from experimental group `n1` sample size from control group `n2` sample size from experimental group `a` significance level

## Details

To calculate d-delta, the mean of the experimental group is subtracted from the mean of the control group, which is divided by the standard deviation of the control group.

d_delta = (m1 - m2) / sd1

## Value

Provides the effect size (Cohen's d) with associated confidence intervals, the t-statistic, the confidence intervals associated with the means of each group, as well as the standard deviations and standard errors of the means for each group.

 `d` d-delta effect size `dlow` lower level confidence interval of d-delta value `dhigh` upper level confidence interval of d-delta value `M1` mean of group one `sd1` standard deviation of group one mean `se1` standard error of group one mean `M1low` lower level confidence interval of group one mean `M1high` upper level confidence interval of group one mean `M2` mean of group two `sd2` standard deviation of group two mean `se2` standard error of group two mean `M2low` lower level confidence interval of group two mean `M2high` upper level confidence interval of group two mean `spooled` pooled standard deviation `sepooled` pooled standard error `n1` sample size of group one `n2` sample size of group two `df` degrees of freedom (n1 - 1 + n2 - 1) `t` t-statistic `p` p-value `estimate` the d statistic and confidence interval in APA style for markdown printing `statistic` the t-statistic in APA style for markdown printing

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35``` ```#The following example is derived from the "indt_data" dataset, included #in the MOTE library. #A forensic psychologist conducted a study to examine whether #being hypnotized during recall affects how well a witness #can remember facts about an event. Eight participants #watched a short film of a mock robbery, after which #each participant was questioned about what he or she had #seen. The four participants in the experimental group #were questioned while they were hypnotized. The four #participants in the control group recieved the same #questioning without hypnosis. hyp = t.test(correctq ~ group, data = indt_data) #You can type in the numbers directly, or refer to the dataset, #as shown below. delta.ind.t(m1 = 17.75, m2 = 23, sd1 = 3.30, sd2 = 2.16, n1 = 4, n2 = 4, a = .05) delta.ind.t(17.75, 23, 3.30, 2.16, 4, 4, .05) delta.ind.t(mean(indt_data\$correctq[indt_data\$group == 1]), mean(indt_data\$correctq[indt_data\$group == 2]), sd(indt_data\$correctq[indt_data\$group == 1]), sd(indt_data\$correctq[indt_data\$group == 2]), length(indt_data\$correctq[indt_data\$group == 1]), length(indt_data\$correctq[indt_data\$group == 2]), .05) #Contrary to the hypothesized result, the group that underwent hypnosis were #significantly less accurate while reporting facts than the control group #with a large effect size, t(6) = -2.66, p = .038, d_delta = 1.59. ```

MOTE documentation built on May 2, 2019, 5:51 a.m.