In the Following Study, Participants Were Randomly Assigned to Receive

question 7

Short Answer

In the following study, participants were randomly assigned to receive humanistic therapy, psychodynamic therapy, or behavioral therapy for their depression. Six months after therapy ended, participants' levels of depression were rated on a Likert scale from 1 (not at all depressed) to 15 (extremely depressed).
$\begin{array}{lcccc}{\text { GROUP }} & \text { N } & \text { MEAN } & \text { STD DEV } & \text { STD ERROR } \\\text { 1 (humanistic) } & 10 & 5.40 & 2.17 & 0.69 \\\text { 2 (psychodynamic) } & 10 & 7.50 & 2.84 & 0.90 \\\text { 3 (behavioral) } & 10 & 5.60 & 3.13 & 0.99\end{array}$


ONEWAY ANOVA: THERAPY bY DEPRESSION
$\begin{array} { l c c c c c } & \text { SUM OF } & & \text { MEAN } & & \\ \text { SOURCE } & \text { SQUARES } & \text { DF } & \text { SQUARES } & \text { F RATIO } & \text { PROB. } \\ & & & & & \\ \text { BETWEEN GROUPS } & 26.87 & 2 & 13.73 & 1.78 & .187 \\ \text { WTHIN GROUPS } & 203.30 & 27 & 7.53 & & \\ \text { TOTAL } & 230.17 & 29 & & & \end{array}$

POST HOC TEST: Tukey-HSD with significance level .05
* Indicates significant differences shown for pairings

$\begin{array}{lll}G & G & G \\r & r & r \\p & p & p \\1 & 2 & 3\end{array}$

$\begin{array}{ll}\text { Mean}& \text { THERAPY }\\5.40 & \text { Grp 1 } \\7.50 & \text { Grp 2 } \\5.60 & \text { Grp 3 }\end{array}$

-What is the dependent variable in this study?

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Definitions:

Horizontal Gene Transfer

The movement of genetic material between unicellular and/or multicellular organisms other than by the "vertical" transmission of DNA from parent to offspring.

dN/dS Ratio

A measure used in genetic studies to quantify the relative rate of non-synonymous (dN) to synonymous (dS) mutations, indicating selective pressure.

Neutrally

In a manner that is unbiased, not favoring one side, or in genetics, referring to mutations that do not affect an organism's fitness.

Positive Selection

The evolutionary process by which alleles that confer a fitness advantage increase in frequency within a population, leading to adaptation.