Help with interpreting papers about CIs

Published Apr 29, 2014

2 Posts

I need help with statistics and interpreting two studies. I have no idea what to write. If anyone could help and explain in simple terms I would be more than grateful!

I have two studies which I need to discuss and make sense of. Study 1 has pre-test mean then following the intervention a post-test mean. In this study there was a control group, also with a pre-test mean and a post-test mean.

The second study tested the same group before and after the intervention.

I need to find the confidence interval of each study. This is where I am stuck. I understand what the CI means. But I need to calculate it. I do not need to know how the actual calculation is done as I am allowed to use a calculator and this is not what is being assessed.

I am looking at the overall success of the intervention and have to use just these two papers to discuss the intervention itself. I need to discuss the p values which I understand, but also the CIs! I need to make sense of both CIs and what this means to the actual intervention... Hope this makes sense!

Study 1.

Pre- and post-intervention values (standard error).

Intervention_________________

Mean (SD) Mean (SD)

Pre-test Post-test __

6.66 (0.15) 5.74 (0.17)

P value*

Waiting room control_________

Mean (SD) Mean (SD)

Pre Post_____

6.31 (0.26) 6.39 (0.27)

P value*

*Significance of pre- to post-intervention change.

Changes in mean pre- and post-intervention symptom scores were calculated and differences were evaluated with paired t-tests, with significance set at

None of the changes was significant for the waiting room controls

Study 2

Pre- and post-intervention values (standard error).

Intervention__________________ Difference t p__

Pre-test Post-test __

Mean (SD) Mean (SD)____________________________

3.15 (2.8) 2.47 (2.6) -0.69 -3.30 0.001

Significance set at

Criterion for significance p