Indusrial Engineering, Des & Analy Experiments please help me out guys. A resear
ID: 2417894 • Letter: I
Question
Indusrial Engineering, Des & Analy Experiments
please help me out guys.
A research study was conducted to examine the clinical efficiency of a new antidepressant. Depressed patients were randomly assigned to one of three groups: a placebo group, a group that received a low dose of the drug, and a group that received a moderate dose of the drug. After four weeks of treatment, the patients completed the Back Depression Inventory. The higher the score, the more depressed the patient. The data is presented below. Compute the appropriate test. What would be the null hypothesis in this study? What would be the alternate hypothesis? What probability level did you choose and why? What is your F_critical? Is there a significant difference between the groups (JUSTIFY)!? If there is a significant difference, where specifically are the differences? Interpret your answer.Explanation / Answer
Answer:(1) There will be no difference in depression levels between the three groups. The groups taking the drug will not be different than the groups taking the placebo.
Answer:(2) There will be a difference somewhere in depression levels between the three levels of drug groups.
Answer:(3) p = .01. There is a risk involved with a Type I error. I do not want to erroneously say the drug works and then later find out that it doesn't.
Answer:(4) Fcrit = 6.93
Answer:(5) Yes - a significant difference exists somewhere between the three groups.
Answer:(6) There is a significant difference between the placebo group and the low dose group (Fcomp = 11.75 and qobs= 4.84, p < .05). There is a significant difference between the placebo group and the moderate dose group (Fcomp = 20.77 and qobs= 6.44, p < .01). There is no significant difference between the low dose and the moderate dose groups (Fcomp = 1.27 and qobs= 1.59, n.s.).
Answer:(7) The drug appears to help alleviate depression. However, as there is no significant difference between taking a low or moderate dose, a low dose would be recommended.
Source SS df MS F Between 1484.9333333 2 742.4666666 11.26 Within 790.8 12 65.9 Total 2275.733333 14