In the Following Study, Participants Were Randomly Assigned to Receive

Essay

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

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

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

-Is this a true experiment or an ex post facto study? How do you know?