Review the article, "Validate to Bring Out the Real Value of Visual  Analytics," provided in the study materials, for an in-depth  understanding of expert validation, predictive validation, external  validation, and cross validation. Conduct a literature review of similar research to compare the model that you completed in Topic 5.  Create a draft outline with the following items in your literature review. (Please create a seperate document answering these questions.) Complete an external and cross validation. Explain  if your validation method is still sufficient and discuss if the model  results are consistent with theories in your field. What are the next steps for your model? Be specific. Is there a need for a model revision? If so, describe what shortcomings you encountered. If not, describe why. What future recommendations would you make to your model if you had another opportunity? What would you do differently? You are required to include at least three scholarly peer-reviewed sources.

For this assignment you will complete two separate investigations: one that uses an independent and one that uses a dependent/paired t-tests. T-testsA teacher is interested in knowing whether different students in her class have different levels of statistics knowledge at the beginning of the course and whether they gain knowledge in statistics over the course of her class. She administered a survey to all of her students asking whether they are pursuing a masters degree or Ph.D. (“Degree”) and entered that information along with their scores on a statistics pre-test (“PreTest”). At the end of the course, she administered the same test again and entered their scores (“PostTest”).For this assignment use StatPrePost.savAnswer questions 1-3 for each of the following two scenarios: Scenario 1: Is there a statistically significant difference between masters degree students and Ph.D. students in terms of statistics knowledge at the beginning of the course?Scenario 2: Is there a statistically significant difference between students’ statistics knowledge at the beginning and the end of the course?Report whether an independent samples or dependent/paired samples t-test should be used.Run the appropriate t-test (include Levene's test for homogeneity of variances for the independent t-test). Report the obtained t value, degrees of freedom (df), and significance level (p-value) for this t-test? If the Levene's test was run, report test statistic and significance level (p-value) for this test.What conclusion should the investigator draw on the basis of this test with regard to the null hypothesis if the alpha is set at .05?Submit your answers to #1-3 in a Word document. Use a page break to separate the independent and dependent t-test sections and label each section accordingly. Please upload your file to Blackboard using the Attach File option.