Elaborate Concepts On The T-test Using Calculations And Spss - 825 Words

Elaborate Concepts On The T-test Using Calculations And Spss (Statistics Project Sample) Content: Statistical InterpretationNameInstitutionExercise 1A t-test was conducted to test whether there was a significant difference between the baselines and post LDL measurements of 15 participants after a nurse-based intervention. The mean difference between the two measurements was -8.2. The test was significant at t(14)=0.0036. This implies there was a statistically significant difference between the Baseline and Pre LDL values. A non-parametric test, the sign test was also used to determine whether a significant difference between the two measures exists. The probability that the median value was less than 0= (0.0461) was significant at alpha=0.05. Similar results were obtained using the Wilcoxon Signed Rank test where the absolute value of the test statistics was significant at 0.00440.005 and the one sided test significant at 0.00220.005. The normal Q-Q plot shows that the data was close to normal since most of the points lie close to the slope line. All the tests giv e a similar outcome; the nurse-based intervention method improved the LDL cholesterol levels for the patients. However parametric tests are much easier to conduct, do not require a lot of data and can be used on various shapes of data. Non-parametric tests require large sample sizes, for example in the sign test, each of the paired samples should be present. These tests do not depend on the distribution of a sample, and the results tend to be invalid.Exercise 2An ACOVA analysis was conducted to determine whether LDL pre was a significant predictor of LDL post. A summary of the model fit shows that 51.68% of the variation was accounted for by the model while the rest was due to chance while the F-value=13.9014 was significant at 0.00250.005. A look at the parameter estimates revealed that LDL Pre was a significant predictor of LDL post at 0.00250.005. Finally, the normal quartile plot shows the data was normal since most of the values lie on and close to the slope line. The regressio n equation obtained was:LDL Post=-74.1888+1.4779489*LDL Pre * Predict the POST LDL and gain using the average Pre LDLLDL Post= -74.1888+1.4779489*138.067LDL Post= 129.8672Gain= -8.1998; -8.2 in exercise 1 * Predictions for pre LDL of 130 and 145LDL Post= -74.1888+1.4779489*130=117.9446Gain= -12.0554; -15 in exercise 1LDL Post= -74.1888+1.4779489*145=140.1138Gain = - 4.8862; 0 in exercise 1The results from exercise 2 seem more accurate since they are not rounded off to whole numbers. Furthermore, while getting the average between the Pre and Post LDL values, data accuracy may be lost due to truncation errors and rounding off. The ANCOVA method seems more appropriate and accurate.Exercise 3 POST 130 =130 Totals Pre 130 2 8 10 =130 13 7 20 Totals 15 15 30 Estimated proportion with LDL less than 130 pre and post;Expected frequency=230*100=6.6667%McNemars statistic2=(8-13)28+13=1.1905The p-value using excel;CHISQ.DIST.RT(1.1905,1)= 0.275229The McNemars test is used to determine whethe r there is an association between paired dichotomous variables. In this case, the p-value 0.2752290.05. This implies the proportions less than 130 pre is not equal to the proportion less than 130 Post. We conclude that there was no association between the case and control variables.Exercise 4Data Analysis Using SPSSA 95% confidence interval was used for all the testsT-TestPaired Samples Statistics Mean N Std. Deviation Std. Error Mean Pair 1 LDL PRE 138.07 15 6.041 1.560 LDL POST 129.87 15 12.420 3.207 Paired Samples Correlations N Correlation Sig. Pair 1 LDL PRE LDL POST 15 .719 .003 Paired Samples Test Paired Differences t df Sig. (2-tailed) Mean Std. Deviation Std. Error Mean 95% Confidence Interval of the Difference Lower Upper Pair 1 LDL PRE - LDL POST 8.200 9.104 2.351 3.158 13.242 3.488 14 .004 SIGN TESTNPar TestsWilcoxon Signed Ranks TestRanks N Mean Rank Sum of Ranks LDL POST - LDL PRE Negative Ranks 10a 8.40 84.00 Positive Ranks 3b 2.33 7.00 Ties 2c T otal 15 a. LDL POST LDL PRE b. LDL POST LDL PRE