A randomized controlled trial investigated the effect of body awareness therapy (BAT) and aerobic exercises on pain and quality of life in patients with tension-type headache. Participants were randomly assigned to 1 of 3 groups: BAT group, aerobic exercise (AE) group, and control group. Main outcomes were pain severity evaluated by a Visual Analog Scale (VAS); pain-related disability measured by the Pain Disability Index (PDI); impact of headaches measured by the Headache Impact Tests (HIT); and quality of life measured by the Short Form Health Survey (SF-36). Baseline characteristics concerning age, weight, height, BMI, VAS, and HIT were not statistically different among the groups (p 0.05). However, there was a statistically significant difference among the groups (p

Question

A randomized controlled trial investigated the effect of body awareness therapy (BAT) and aerobic exercises on pain and quality of life in patients with tension-type headache.  Participants were randomly assigned to 1 of 3 groups:  BAT group, aerobic exercise (AE) group, and control group.  Main outcomes were pain severity evaluated by a Visual Analog Scale (VAS); pain-related disability measured by the Pain Disability Index (PDI); impact of headaches measured by the Headache Impact Tests (HIT); and quality of life measured by the Short Form Health Survey (SF-36).  Baseline characteristics concerning age, weight, height, BMI, VAS, and HIT were not statistically different among the groups (p > 0.05).  However, there was a statistically significant difference among the groups (p < 0.05) in mean baseline PDI values.  Further evaluation of baseline PDI values revealed the following: Which of the following is likely to be the most valid measure of central tendency for baseline PDI data?
A)Mean and median both equally valid
B)Mean, median, and mode all equally valid
C)Mean only
D)Median only
E)Mode only

Quizplus · Accepted Answer

Explanation: 11ec2b69_c0e1_d9cd_8f63_cdb7980ad841_MD0005_00 Continuous variables are often summarized through measures of central tendency such as the mean, median, and mode. Continuous variables that follow a normal distribution are symmetrical, with values for the mean, median, and mode that lie very close to each other (mean ≈ median ≈ mode). For normally distributed continuous data, the mean is the most valid choice for central location. Continuous variables that do not follow a normal distribution are asymmetrical and exhibit negative or positive skewness (ie, observations with extreme values [outliers] on either side of the distribution): A negatively skewed distribution has >1 small-valued outliers and mean < median < mode. A positively skewed distribution has >1 large-valued outliers and mean > median > mode. For skewed distributions, the median is a more representative and valid measure of central location than the mean. This study found that the mean baseline Pain Disability Index (PDI) values are statistically different among the body awareness therapy (BAT) group, the aerobic exercise (AE) group, and the control group (43.85, 33.27, and 28.71, respectively; p < 0.05). However, the distribution of baseline PDI appears to be skewed in all 3 groups as follows: AE group: Positively skewed with mean (33.27) > median (31.48) > mode (30.94) BAT group: Positively skewed with mean (43.85) > median (30.41) > mode (27.53) Control group: Negatively skewed with mean (28.71) < median (30.85) < mode (31.01) In particular, the distribution of baseline PDI in the BAT group is considerably skewed, as the mean, median, and mode are relatively distant from each other. Consequently, the median, not the mean, represents the most valid measure of central tendency for summarizing and comparing baseline PDI values among the 3 groups (Choices A, B, and C). (Choice E) The mode is commonly used to describe categorical variables (qualitative). Educational objective: In a positively skewed distribution, the mean is the central tendency measure most shifted in the positive direction (to the right), followed by the median, and then the mode, whereas in a negatively skewed distribution, the mean is the central tendency measure most shifted in the negative direction (to the left), followed by the median, and then the mode. In such situations, the median is a more valid measure of central tendency than the mean.

A Randomized Controlled Trial Investigated the Effect of Body Awareness