5) Which of the following is a method for controlling for effect modification/interaction in the analysis phase only of a study? a) Restriction b) Matching c) Randomization d) Stratification e) None of the these

In a study of Europeans from a variety of professions were asked if they considered themselves left-handed, right-handed, or ambidextrous. The results are given. a) Test for an association between handedness and career for these five professions. Note: Ambidextrous is considered a type of handedness so you should use all 5 rows and 3 columns for this work. What do you conclude at the 5% significance level? What do you conclude at the 1% confidence level? Make sure you show all the steps. b)Can we conclude, at the 5% significance level, that left-handedness is equally distributed among the five professions? Make sure you show all the steps.  Profession Right Left Ambidextrous Total Psychiatrist 101 10 7 118 Architect 115 26 7 148 Orthopedic Dr 121 5 6 132 Lawyer 83 16 6 105 Dentist 116 10 6 132 Total 536 67 32 635

Is this right?

9. Nicotine patches are often used to help smokers quit. Does giving medicine to fight depression also help? A randomized double-blind experiment assigned 244 smokers to receive nicotine patches and another 245 to receive both a patch and the antidepressant drug bupropion. After a year, 40 subjects in the nicotine patch group had abstained from smoking, as had 87 in the patch-plus-drug group. (a) Construct and interpret a 99% confidence interval for the difference in the proportion of smokers who abstain when using buproprion and a nicotine patch and the proportion who abstain when using only a patch. (b) Based only on this interval, do you think that the difference in proportion of abstaining smokers is significant? Justify your answer.

Explain if a simple effect is significant and involves more than two groups, Tukey’s HSD Test?

The brightness of films produced by 3 different manufacturers has been compared using 3 different development processes: Kodak Fuji B C Agfa B A C 26 A 32 32 38 23 27 30 25 27 32 43 41 27 30 31 34 29 28 32 24 31 30 37 27 44 38 36 25 25 25 25 26 30 50 40 35 22 32 47 36 34 27 27 25 Carry out analysis of variance and interpret the results. 222

4. A researcher was examining the effectiveness of different treatments in reducing depressive symptoms in children under the age of 10, who have been victims of child abuse. This study involves 207 children suffering from clinical depression, who were randomly assigned into four treatment conditions: Treatment A: CBT, Treatment B: Family Therapy, Treatment C: Psychoanalysis, Treatment D: Wait List. Using a significance level of 0.05, answer the following questions. Improvment Improvment Improvment Therapy Wait List CBT Family Between Groups Within Groups Total Psychoanalysis Based on Mean Based on Median Based on Median and with adjusted df Based on trimmed mean Sum of Squares Test of Homogeneity of Variances 1002.541 7085.788 8088.329 ANOVA df 3 203 206 Tests of Normality Kolmogorov-Smirnova df Statistic .105 119 .108 .092 Levene Statistic 1.934 1.932 1.932 1.940 Mean Square 334.180 34.905 df1 3 3 3 3 60 56 48 43 df2 F 9.574 203 203 164.105 203 Sig. Sig. .097 .048 .200* .200* .000…

Table 1 gives a summary of sample autocovariance and autocorrelation functions. Table 1 1 x₁ Ŷ₁ P₁ 1 0 0 0 2 1 مدام 3 2 4 2 c|5 5 0 0 0 (a) Calculate the missing values of sample autocovariance and autocorrelation functions in Table 1.

12) A professor wanted to compare the ages of male and female graduate students at her university. She collected a random sample of male and a random sample of female students in Spring 2022 semester. Data (in years) are given below. Is there sufficient evidence to conclude the difference in the means (average age) is statistically significant? use 5% (α = 0.05) significance level.  Male graduate students: 29, 35, 36, 28, 24, 30, 31, 25, 27, 29, 41, 39, 38, 35,  30 Female graduate students:  28, 27, 29, 24, 28, 24, 35, 37, 26, 29, 28, 36, 28, 35, 28 a) Write the null hypothesis and alternative hypothesis to test the above claim. b)  What is the value of the test statistic? c)  What is the degrees of freedom of the t distribution of the test statistic? d) What is the p-value? e) Write your conclusion and express in terms of the evidence for the indicated calim.