Since we are measuring the scores of participants at two different times, a paired sample t-test is the best option to compare the means of the total scores for each scale.
A dependent samples t-test was conducted to compare improvements in emotional disturbance before and after a positive treatment for a week. There was a statistically significant difference from before the positive treatment (M = 50.85, SD = 23.01) and after the treatment (M = 42.85, SD = 21.69), t(39) = 3.519, with a medium effect size (Cohen's d = 0.556). These results indicate that, when exposed to positive treatment, the effect on mental health can be reduced in terms of emotional disturbance.
A dependent samples t-test was conducted to compare improvements in self esteem before and after a relaxing treatment for a week. There was a statistically significant difference from before the positivity treatment (M = 14.73, SD = 5.66) and after the treatment (M = 16.25, SD = 3.91), t(39) = -2.277, with a small effect size (Cohen's d = 0.36). These results indicate that self esteem could be boosted when exposed to positive treatment, although not as effectively.
Both of the results are statistically significant, therefore we can reject the null hypothesis. The results clearly indicate positivity does have an effect on both mental health and self esteem, albeit moderate effect size.