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101A_assessment_one_review_answers_feb_7 - Statistics 101A...

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Statistics 101A Review for class assessment one Professor Esfandiari Question one: A researcher wants to examine the effect of two major classes of antidepressants -MAOIs, SSRIs, on patients with and without sleep disorder (insomnia or lack of insomnia). There are ten medication in class one and ten types of medication in class two. 180 depressed individuals 50% of whom also have insomnia participate in the study. He randomly picks one MAOI and one SSRI. He randomly assigns one third of the patients who suffer from insomnia and one third of those who do not to take either the MAOI selected, the SSRI selected, or a placebo. He measures their level of depression prior to and after taking the medication for six months. a) Identify the independent and the dependent variables. The independent variables are class of antidepressant (three levels), having or not having insomnia (two levels), and the outcome variable is drop in depression. b) Draw a schematic of the data Patients with insomnia Patients without insomnia MAOI SSRI Placebo MAOI SSRI Placebo 1 2 3 ni,11 1 2 3 ni,1,2 1 2 3 ni, 1, 3 1 2 3 ni,2,1 1 2 3 ni,2,2 1 2 3 ni,2,3 c) What statistical method do you suggest for analyzing the data collected. crf 3,2 mixed effects. Medication is random effect and insomnia is fixed effect d) Write the expected values for testing the relevant nulls. (see table 8.4-1) page 363 CRF handout part one This model is A random and B fixed Source of variation Expected value A) Drugs type (random) or alpha effect s^2 (e) + nqs^2 (a) B) Insomnia (fixed) or beta effect s^2 (e) + s ^2(ab) + npåb^2 (k)/q-1 AM) Drug* insomnia or alpha beta effect s^2 (e) + s ^2(ab) Within cell or residual (eijk) s^2 (e) This is how F values are calculated F(A) = {s^2 (e) + nqs^2 (a))/s^2 (e) F(B) = {s^2 (e) + s ^2(ab) + npåb^2 (k)/q-1}/{s^2 (e) + s ^2(ab)} F(AB) = { s^2 (e) + s ^2(ab) }/ s^2 (e) Whereas in the CRF PQ with fixed effects we to find F(A), F(B) and F(AB) we divided by MS (within) or s^2 (e) in all three cases.
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Question 2 : The following table was reported in a pediatrics journal for 100 mothers that smoked and 100 who did not smoke. The smoking and non-smoking mothers were similar on other potential confounding factors that could influence the weight of the babies.
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