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The Type 1 error refers to rejecting the null hypothesis when it is true. The Type 2 error is when one rejects the alternative hypothesis even though it is true.
3. Parametric and non-parametric tests
Parametric tests usually deal with samples that have a normal distribution and that are measured with means and standard deviations. T-tests and ANOVA are examples of this comparing one group against another. The Pearson would be used with correlation. Non-parametric tests, however deal with populations where there is no or vague assumptions about the shape or parameters of the population (for instance when one is dealing with a very small sample of offenders that cannot be measured with parametric instruments). Non-parametric tests include Wilcoxon rank-sum test and Kruskal-Wallis test as t-test / ANOVA contrast as well as Spearman's rank correlation instead of Pearson's. (Parametric and Nonparametric: Demystifying the Terms)
4. T-test and ANOVA
The t-test is used for 2 groups, control and experimental. The Anova is used for more than 2 groups. Both are parametric tests. The MANOVA is used for when many different components are expected to be involved in the study and researcher wants to study which one is likely to be most responsible for results. There are three types of t-test:
1. One-sample-t-test - Compares mean of sample with known population mean
2. The independent two-sample t-test is used to determine if the means of two independent samples are equal (for...
Paired samples t-test - if the means of a paired sample is equal (for instance comparing the test scores of a group that received that same test on two different occasions).
4. General issues of using recidivism as a dependent measure in any study are the following:
The construct of recidivism has to be thoroughly defined -- this includes the characteristics of the offenders: their sex, their age, their geographic background, their socio-economic background, and level of education, crime, reasons why they perpetrated the crime, ethnicity, and so forth. Recidivism is too general and object of investigation has to be thoroughly defined so that researcher is sure that objectives of study are met.
In this study too the construct has to be clearly defined in order to make sure that the participants of each group are closely matched and that all meet the desired requirements of 'recidivism'. Only then can one tell whether the intervention really worked or whether it failed.
Sources
Cohen, R.J., & Swerdlik, M.E. (2004). Psychological testing and assessment (6th edition). Sydney: McGraw-Hill
Greenfield ML, Kuhn JE, Wojtys EM. (1998) A statistics primer. Confidence intervals. AmJ Sports Med.; 26:145 -- 149
Parametric and Nonparametric: Demystifying the Terms
http://www.mayo.edu/mayo-edu-docs/center-for-translational-science-activities-documents/berd-5-6.pdf
Sources
Cohen, R.J., & Swerdlik, M.E. (2004). Psychological testing and assessment (6th edition). Sydney: McGraw-Hill
Greenfield ML, Kuhn JE, Wojtys EM. (1998) A statistics primer. Confidence intervals. AmJ Sports Med.; 26:145 -- 149
Parametric and Nonparametric: Demystifying the Terms
http://www.mayo.edu/mayo-edu-docs/center-for-translational-science-activities-documents/berd-5-6.pdf
The median is the mid-point of a given data set; rather than the mean, which produces a single number that takes into account the extremes of the data set as well as the middle, the median tends to be more stable, finding the half-way point between extremes rather than directly incorporating them. For wage comparisons, especially over time, the median is useful and an excellent choice of statistical tool precisely
Combat and Substance Abuse Posttraumatic stress disorder (PTSD), as a consequence of combat experience, is believed to be a significant risk factor for substance abuse. This theory has been undermined to some extent by recent findings which suggest mental illness, apart from PTSD, may be a stronger predictor. Although combat-related PTSD may significantly contribute to the prevalence of substance abuse among veterans, the dominant substance abuse risks are the same for
Here, the dependent variable is identified as the proclivity toward suicide. The researchers identify four independent variables due for measurement. These are identified as psychological distress, hopelessness, drug abuse, and relationship discord. (Kaslow et al., p. 13) The study collected data using interviewing techniques that would occur within a 24 to 72 window of the subject's hospital admission. Findings would be measured in the categories of Psychological Risk Factor Variables
(p. 226) Findings and Discussion Paulessen-Hoogeboom et al. (2008) present us with a number of key findings that have such pervasive implications for parenting. All toddlers engage in behaviors such as biting, hitting, screaming, or otherwise acting out. Such behaviors arise as a result of negative emotions. Parents often find these behaviors hard to deal with -- along with other children and other caregivers. The response by others in the children's
In a study of 50 failed states and political structures, the authors found that in nearly every case (47 of the 50) there was a direct link between out of control population growth and the depletion of specific resources that allow both the country's government and economy the means to create a stable society (Levin, and Renelt, 1992, pp. 954). Overpopulation was but one of a set of variables
Abused children develop antisocial behavior that persists through three continuous generations. Such behavior grows out of angry, aggressive parenting and an overall negative home environment, perpetuated by sibling collusion, economic and biological factors. These children exhibit this in preschool by committing at least one antisocial behavior each day in class. As dysfunctional adolescents, their romantic lives and eventual marriages also fail. African-American children suffer from the affliction than Caucasian children.