A three-arm, randomized crossover trial is conducted to determine whether the profile of circulating micro RNAs (miRNAs) is altered after acute resistance training with blood flow restriction (BFR), as compared with unrestricted low- and high-volume training. Eighteen healthy volunteers (mean age 25) are enrolled. The arms are single bouts of leg flexion/extension resistance training at: 70% of the individual single-repetition maximum (1RM)30% of the 1RM30% of the 1RM with BFR (artificially applied by a cuff at 300 mm Hg)
During each training intervention, load-associated outcomes (fatigue, heart rate, and exhaustion) are monitored. Acute effects (circulating miRNAs and lactate) are determined using pre- and postintervention measurements. Preliminary results show that lower lactate concentrations tend to correspond with lower miR-143-3p expression, and that the relationship is very strong and statistically significant. Based on this information, which of the following statements is most correct about the correlation coefficient r for this relationship?
A)r is negative and probably closer to −1 than to 0
B)r is negative and probably closer to 0 than to −1
C)r is positive and probably closer to 0 than to 1
D)r is positive and probably closer to 1 than to 0

Question

A three-arm, randomized crossover trial is conducted to determine whether the profile of circulating micro RNAs (miRNAs) is altered after acute resistance training with blood flow restriction (BFR), as compared with unrestricted low- and high-volume training.  Eighteen healthy volunteers (mean age 25) are enrolled.  The arms are single bouts of leg flexion/extension resistance training at: 70% of the individual single-repetition maximum (1RM)30% of the 1RM30% of the 1RM with BFR (artificially applied by a cuff at 300 mm Hg)
During each training intervention, load-associated outcomes (fatigue, heart rate, and exhaustion) are monitored.  Acute effects (circulating miRNAs and lactate) are determined using pre- and postintervention measurements.  Preliminary results show that lower lactate concentrations tend to correspond with lower miR-143-3p expression, and that the relationship is very strong and statistically significant.  Based on this information, which of the following statements is most correct about the correlation coefficient r for this relationship?
A)r is negative and probably closer to −1 than to 0
B)r is negative and probably closer to 0 than to −1
C)r is positive and probably closer to 0 than to 1
D)r is positive and probably closer to 1 than to 0

Quizplus · Accepted Answer

Explanation: 11ec2b69_c0ea_3e40_8f63_9becc5aa5d10_MD0005_00 The correlation coefficient r describes the direction (negative or positive) and the strength (values closer to −1 or 1 indicate stronger relationships) of the linear relationship between 2 quantitative variables: r < 0 indicates that as one variable increases, the other variable decreases. This means that lower values of one variable tend to relate to higher values of the other variable, and vice versa. r > 0 indicates that both variables increase (or decrease) together. This means that lower values of one variable tend to relate to lower values of the other variable, and vice versa. In this study, results reveal that lower lactate concentrations tend to correspond with lower miR-143-3p expression. This means that both variables increase (or decrease) together, so the correlation coefficient must be positive (Choices A and B). Study results also show that the relationship is very strong and statistically significant. Because the relationship is described as very strong, the correlation coefficient must be closer to 1 than to 0 (Choice C). Educational objective: The correlation coefficient r describes the direction (negative or positive) and the strength (values closer to −1 or 1 indicate stronger relationships) of the linear relationship between 2 quantitative variables. It does not necessarily imply causality.

A Three-Arm, Randomized Crossover Trial Is Conducted to Determine Whether