QUESTION 1 (Introduction):
· Briefly introduce your report, explicitly stating your research question and relevant concepts. You need not treat this as a short paper, but may wish to cite work read in other classes or from sociology (or other academic) journals.
· Define your population of interest, and define the available sample. What is the sample size, and what is the population size? (Note: The population of interest is not the full NLHLS dataset. There would be no reason to make inferences to a set of respondents we already know, and don’t particularly care, about.) Comment on any strengths or weaknesses of the sample for your study, including the sample size, any biases you might suspect, any advantages or disadvantages of the sampling procedure, and anything you would change about that procedure.
· For each variable that you selected, identify its variable name, variable label, operational definition (including value labels, if appropriate), relationship to the research question (i.e. concepts) chosen, and level of measurement, noting any changes introduced in recoding. Provide a concise (brief but complete) univariate analysis of each variable. Pay special attention to missing values – if you have two variables with many missing cases, you may not have enough cases which are valid for both variables.
QUESTION 2 (Determination of Sample Size):
· For the interval variable used in questions 5 and 6, what is the minimum sample size you would need to come within a specified range of error 99% ofthe time?
· Describe each number plugged into the formula, and explain what the sample size n that you computed represents. Be sure to specify a margin of error beforehand, and to be explicit about justifying why you chose it. Assume that your sample statistics are reasonable estimates for the unknown in this future-oriented calculation; i.e. use the sample standard deviation since you do not have the population’s.
QUESTION 3 (Nominal Hypothesis Test):
· Conduct a one-sided statistical test for the hypothesis concerning your nominal variable, using the 0.05 level of significance.
· List all steps and assumptions you would need in testing the null hypothesis, including statements of both hypotheses, show computations, interpret the test statistic and the p-value, make the decision and fully indicate why you made the decision, and indicate what this decision says about your research question or how it might affect your addressing that question.
· Be sure to attach a copy of the data used to formulate your hypothesis and state the source of the hypothesized value, the sample studied by that source, and the population of interest to that source and assessed by that sample. Include in your citation (if this information is not included on your printed or photcopies attachment) the title, year of publication, publisher, author if relevant, page of table if relevant, and table number if relevant.
QUESTION 4 (Nominal Confidence Interval):
· For the nominal variables used in question 3, report the sample proportion for a category of the variable and then construct a 95% confidence interval for this category.
· Describe each number you plugged into the computation, and interpret the confidence interval.
· Be certain to clearly justify use of the category you select.
QUESTION 5 (Interval Hypothesis Test):
· Conduct a two-sided statistical test of the hypothesis concerning your interval variable, using an alpha of 0.01
· List all steps and assumptions you would need in testing the null hypothesis, including statements of both hypotheses, show computations, interpret the test statistic and the p-value, make the decision and fully indicate why you made the decision, and indicate what this decision says about your research question or how it might affect your addressing that question.
· Be sure to attach a copy of the data used to formulate your hypothesis and state the source of the hypothesized value, the sample studied by that source, and the population of interest to that source and assessed by that sample. Include in your citation (if this information is not included on your printed or photcopies attachment) the title, year of publication, publisher, author if relevant, page of table if relevant, and table number if relevant.
QUESTION 6 (Interval Confidence Interval):
· Construct a 99% confidence interval around the sample mean of the variable used in question 5.
· How is this interval consistent with the result of your hypothesis test, or is if it isn’t how do you explain that inconsistency? Why should they be consistent, and why might they contradict? If they contradict, do you have reason to consider one more persuasive than the other?
QUESTION 7 (Subsample Confidence Intervals):
· Construct separate confidence intervals for the interval variable, one for each of two groups (or categories) of your nominal variable. (If you nominal variable has more than two categories, you need not analyze the others.)
· You will need to use Select Cases twice. (Be sure to reselect “All Cases” in between, and to use Filter and not Delete.)
· Be sure to justify your choice of test categories: why would the distribution (center or spread) of the interval variable differ between these two groups? If you find that it does not differ, account for that.
· Be sure to begin with univariate analyses (shape, central tendency, and dispersion) of the separate distributions for each of the groups you will analyze.
· Are there any unanalyzed categories of this variable that might differ as well? If so, how & why?
QUESTION 8 (Difference of Means):
• Test for a difference of means for your interval variable between the two chosen nominal categories. Include all steps, and make explicit conclusions both about variation in the distributions and about what sort of relationship you believe exists between the variables. (Warning: we are not yet analyzing correlation, association, or causation, so do not make those sorts of claims.)
