A pediatric cardiologist decides to determine whether there is a relationship between body composition and blood pressure in a random sample of children and adolescents age 5-15. He used standard procedures to collect anthropometric measurements that included weight, height, hip circumference (HC), and waist circumference (WC). Systolic blood pressure (SBP) and diastolic pressure (DBP) readings were taken at least 3 times at 5-minute intervals after the participants had been seated, and average SBP and DBP readings were calculated based on these measurements. Which of the following statistical tests is adequate to determine whether there is a relationship between WC and average DBP?

Question

A pediatric cardiologist decides to determine whether there is a relationship between body composition and blood pressure in a random sample of children and adolescents age 5-15.  He used standard procedures to collect anthropometric measurements that included weight, height, hip circumference (HC), and waist circumference (WC).  Systolic blood pressure (SBP) and diastolic pressure (DBP) readings were taken at least 3 times at 5-minute intervals after the participants had been seated, and average SBP and DBP readings were calculated based on these measurements.  Which of the following statistical tests is adequate to determine whether there is a relationship between WC and average DBP?

Quizplus · Accepted Answer

11ec160b_372a_dd4f_9249_330e3e5423e3_MD0001_00 Variables are broadly classified as qualitative (ie, categorical) or quantitative (ie, continuous) based on their scale of measurement. Qualitative variables (eg, type of treatment, blood type) represent categories or groups whereas quantitative variables (eg, temperature, glucose levels) represent numerical values. The scale of measurement of the dependent (eg, outcome) and independent (eg, exposures, risk factors) variables in a study determines the correct statistical test for any given situation. Correlation analysis is a statistical technique used to assess the strength and direction of a linear relationship between 2 quantitative variables (often, but not always, a dependent and an independent variable). In this study: Correlation analysis can determine whether there is a relationship between DBP and WC. A statistically significant correlation coefficient indicates that DBP and WC have a linear relationship (ie, the null hypothesis is rejected) that is either positive (as WC increases, DBP increases) or negative (as WC increases, DBP decreases). (Choice A) The analysis of variance (ANOVA) test compares the mean of a quantitative variable of ≥3 independent groups, as in a study comparing serum ferritin concentrations (ie, quantitative variable) in children (age 0-12), adolescents (age 13-17), adults (age 18-59), and seniors (age ≥60). (Choice B) The chi-square test evaluates the association between 2 categorical variables, as in a study evaluating the association between sex (ie, "male" and "female") and myocardial infarction (ie, presence of myocardial infarction, absence of myocardial infarction). (Choice D) Meta-analysis is a quantitative statistical technique used to combine and analyze data from several studies to conduct an analysis with a greater statistical power than that of the individual studies. (Choice E) The two-sample t-test compares the mean of a quantitative variable between 2 groups, as in a study comparing serum ferritin concentrations (ie, quantitative variable) in male and female patients. Educational objective: Correlation analysis is a statistical technique used to describe the strength and direction of a linear relationship between 2 quantitative variables. __________ References: Correlation coefficients: appropriate use and interpretation. (http://www.ncbi.nlm.nih.gov/pubmed/29481436)

A Pediatric Cardiologist Decides to Determine Whether There Is a Relationship