Indeed,to study the relationship between Smoking and GPA one can useregression. To study the relation of smoking on GPA, one will use thePearson correlation coefficient where the variables will be the GPAand Number of cigarettes smoked a day. If the coefficient is negativewith the GPA, it shows that smoking has deleterious effects. If thecoefficient is positive, then smoking has positive effects on the GPAscores. The coefficient itself shows the magnitude whether therelationship is strong or weak or moderate (Hauke & Kossowski,2011).
Tostudy if there is a difference between the GPA of students who smokeand the students who do not smoke, one will have to compare means ofGPA scores of students who smoke and the GPA score of students who donot smoke by doing a one sample t-test (Stevens, 2012). If theP-value is less than 0.05, then it means there is a significantdifference between in GPA scores of students who smoke and the oneswho do not hence smoking has an effect on GPA scores. If the p-valueis greater than 0.05, then there is no significant difference in GPAscores of smoking students and the non-smokers hence smoking has noeffect on GPA scores (Samuels,2012).
Thestudy on the relation of usage of drug x and the tumor size indeedrequires a Pearson correlation test (Powers, 2011). With a negativePearson correlation coefficient, there is indication that the usageof drug x is negatively related with the tumor size (Sarantakos,2012). On the other hand, if the coefficient is positive it meansthat the usage of drug x is positively related to the tumor size inthat the people who used the drug x for more days had a smaller tumorthan the people who used it for a short time.
Thestudy under consideration was not an experimental study. Owing tothis, causation would not be established(Hopkins et al., 2009).This explains the need to find out why there is relation betweenalternative plausible for usage of drug X and the size of tumor.Indeed, tumor may decrease with time without consideration of thedrug usage. For sure, the circumstances at hand is a pointer that thestudy justifies the future experimental testing of drug x astreatment for tumors.
Hauke,J., & Kossowski, T. (2011). Comparison of values of Pearson`s andSpearman`s correlation coefficients on the same sets of data.Quaestiones geographicae, 30(2), 87-93.
Hopkins,W., Marshall, S., Batterham, A., & Hanin, J. (2009). Progressivestatistics for studies in sports medicine and exercisescience. Medicine+Science in Sports+ Exercise, 41(1),3.
Powers,D. M. (2011). Evaluation: from precision, recall and F-measure toROC, informedness, markedness and correlation.
Samuels,M. L., Witmer, J. A., & Schaffner, A. (2012). Statistics for thelife sciences. Pearson education.
Sarantakos,S. (2012). Social research. Palgrave Macmillan.
Stevens,J. P. (2012). Applied multivariate statistics for the socialsciences. Routledge.