Statistics Final

Part 1: Descriptive Statistics

Instructions: Answer each of the following questions using the data set for this assignment.

• List all of the variables in the data set and explain their scale of measurement (nominal, ordinal, interval, or ratio).
• Describe the shape of the frequency distributions for the pre-test, post-test, IQ, internal locus of control, and self-efficacy variables according to symmetry, skewness, and modality.
• What percentage of participants had an IQ of 110? Over 134? Less than or equal to 120? From 115 to 130?
• What percentage of participants had a self-efficacy score of 12 or higher? Score equal to 9? Score equal to 6 or less? Score from 5 to 8?
• What is the mean, median, mode, range, standard deviation, and variance for pre-test, post-test, IQ, internal locus of control, and self-efficacy? What do these results tell you about each variable? Why did we not calculate these statistics for sex or feedback?
• What is the z score for the following participants’ post-test score? What does each of these z scores tell you about the participant’s raw score?
  • Participant 5
  • Participant 10
  • Participant 21
  • Participant 24
• Calculate the area under the normal curve for the following internal locus of control scores: between 6 and 9; below 4; above 7; between 2 and 5. What do these areas represent?

Part 2: Inferential Statistics

Instructions: Four studies are described below. For each study, answer the following questions using the study description and the data set:
A. What are the variables in this specific study? Identify each as an independent or dependent variable, or a covariate.

B. What are the null and alternative hypotheses for this specific study? Provide the statistical notation and written explanation for each.

C. Explain the specific Type I and Type II errors for this study.

D. Would the researcher want to conduct a one- or two-tailed test for significance for this study? Explain.

E. What statistical test (correlation, regression, multiple regression, t test, ANOVA, ANCOVA) would you conduct to test the hypothesis(es) for this study? What specific type of the test (e.g., independent samples, repeated measures, one-way, etc.) would you conduct? Explain your choices.

F. Provide a summary of the results, including the necessary information based on the test(s) conducted, as noted below. You only need to provide the information related to the test(s) conducted (some might require more than one):

• Correlation & Regression – include results in sentence format, correlation coefficient, description of type of correlation and significance, interpretation of the results, scatterplot with the regression line, regression equation for the data set (choose which of the variables from this specific study should be used for X and Y), predictions using the regression equation (choose at least 4 values for X to plug into your regression equation to get Y), description of the standard error of estimate, and conclusions regarding the hypothesis.
• Multiple Regression – include results in sentence format, correlation coefficients, description of type of correlations and significance, interpretation of the results, explanation of regression procedure used, scatterplot with the chosen model’s regression line, regression equation for the chosen model (choose which of the variables from this specific study should be used for the predictors and for Y), predictions using the regression equation (choose at least 4 values for each of the various predictors to plug into your regression equation to get Y), and description of R2 and F values for the chosen model.
• t Test – include results in sentence format, t value, statistical significance of difference, explanation of how you know, comparison of means, 95% confidence interval, and conclusions regarding the hypothesis.
• ANOVA & ANCOVA – include results in sentence format for each main effect and interaction, significance of difference for each, explanation of how you know, ANOVA table, interaction graph and explanation (if applicable), post-hoc comparisons (if applicable), covariate (if applicable), and conclusions regarding the hypothesis(es).

Studies: Answer questions A-F above for each of the following research studies. Treat each study separately.

1. A researcher wants to look at the relationship between post-test scores and self-efficacy scores. If the relationship is significant, the researcher would like to predict self-efficacy scores from post-test scores. The research would also like to consider predicting post-test scores using a variety of predictors (i.e., pre-test, IQ, internal locus of control, and/or self-efficacy).
2. A researcher wants to look at the effect of time on test scores, believing anagram scores will change from the pre-test to the post-test.
3. A researcher exposes participants to no feedback (none), controlling feedback, or informative feedback, and then measures their post-test scores. The researcher believes that post-test scores for those in the informative condition will be higher than those in the no (none) or controlling conditions. After conducting the analyses, the researcher decides to evaluate the impact of IQ as a covariate.
4. A researcher wants to look at the effects of sex and feedback on internal locus of control. The researcher believes that those who are in the informative feedback group will have higher internal locus of control than those who are in the controlling or no feedback groups. In addition, females are expected to have higher internal locus of control than males. The females in the informative feedback condition are expected to have higher internal locus of control than all other groups (females in the controlling or no feedback condition and males in any feedback condition).

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Solution: The downloadable solution consists of 28 pages, 1641 words and 36 charts.
Deliverable: Word Document