Assignment 4 t-Te... CJUS 3312 FE CSUSB Assignment 4: t-Tests and ANOVA (20 points) IMPORTANT: Do not to round intermediate calculations. If it's necessary, round a number to 5 decimal places. 1 Independent Sample t-Test Some research indicates that gender is a factor that influences recidivism among offenders. You hypothesize that there is a difference in the mean number of rearrests between male and female offenders. The table below shows the mean number of rearrests after being released from prison for a sample of 201 male offenders and 101 female offenders. Using the 0.05 significance level, test the null hypothesis that there is no difference between the two groups (i.e., the two population means are equal). Male Female X1 - X , n: 201 101 Mean: 4 2 (n, -1)s'1 + (n, -1)s'2 ", + n SD: 3 2 1 +12 -2 2 1. Is the research hypothesis one-tailed or two-tailed? 2. Calculate the test statistic (You can use Excel to find it in a minute.) Obtained t value: Round your answer to 2 decimal places. Can you reject 3 4. Interpret your answer for Q3 (in one sentence).CJUS 3312 CJUS 3312 Dependent Sample t-Test ANOVA (ANOVA will not be on the exam) A well-evaluated cognitive behavioral program is administered to a sample of 15 youths on juvenile probation to Researchers have suggested that females who have more friends are at greater risk for receiving delinquent teach them how to reduce levels of aggression. You are interested in whether youth's aggression levels reduce pressure. To test their notion, you take a random sample of girls and classify them into one of three groups: after the program. You hypothesize that the mean aggression level drops after the program (1) those who have a lot of friends, (2) those who have some friends, and (3) those who have a few friends. Using the 0.05 significance level, test the null hypothesis that there is no difference in aggression level before Then, you ask each girl to self-report the number of delinquent offenses her friends had encouraged her to do. and after the cognitive-behavioral program (i.e., the program has no effect on aggression level). Before and after results are presented in the table below. Using the 0.05 significance level, test the null hypothesis that there is no difference among the three groups (i.e., the three population means are equal). The following table shows the number of delinquent acts encouraged by friends for each girl in one of the three groups. Aggression Levels ED Before After 18 15 " ED' -(ED) Number of Delinquent Acts 13 n- 1 Encouraged by friends 14 14 Lots of Some Few 16 14 Friends Friends Friends 10 7 5 2 17 14 5 14 11 15 14 10 11 6 2 Mean 9. Find the total, between-groups, and within-group Sum of Squares (Use Excel to find it in a minute.) 5. Is the research hypothesis one-tailed or two-tailed? Total SS: Between SS: Within SS: 6. Calculate the test statistic (You can use Excel to find it in a minute.) 10. Calculate the test statistic (Use Excel to find it in a minute.) Obtained t value: Round your answer to 2 decimal places. Obtained F value: Round your answer to 2 decimal places. 7. Can you reject the null hypothesis? EXPLAIN WHY (in one sentence). "Be sure to write the critical value. Use the Critical Value Table B 2, which can be found in the "DATA" section 11. According to the Critical Value table, the critical value of F statistic is 3.56 (at the 0.05 significance level). Can you reject the null hypothesis? 8. Interpret your answer for Q7 (in one sentence)