Correlation between difficulty & discrimination indices of MCQs in formative exam in Physiology.

Introduction: Difficulty index (P) and discrimination index (D) are the parameters used to evaluate the standard of multiple choice questions (MCQs) in examination. Accordingly the standard of MCQs can be interpreted as excellent, acceptable or poor. This study was intended to find out the standard of MCQs in formative examination in Physiology. The study also intended to find out correlation between P and D. Materials and Methods: There were 240 MCQ items, taken from the past 4 year batches of 100 students and were analyzed for level of difficulty and discrimination index. The relationship between them for each test item was determined by Pearson correlation analysis using SPSS 11.5. Results: There was a wide distribution of item difficulty indices (8.57 to 95.71) and discrimination indices (-0.54 to 0.8).The mean difficulty index (P) was 52.53 + 20.59 and mean discrimination index was 0.30+ 0.18. On average, about 23% of the MCQ items were easy (P >70%), while about 15% were difficult (P <30%). The remaining 62% items were within acceptable range (30 to 70%). In all 4% of the items showed negative discrimination and 21% of the items exhibited poor discrimination. The remaining 75% of the items were in the range of acceptable to excellent discrimination. The discrimination index exhibited slight positive correlation with difficulty index (r = 0.191, P=0.003<0.01). The maximal discrimination (D=0.6-0.8) was observed with moderately easy/difficult items (P = 40% - 60%). Conclusion: The majority (75%) of the items was acceptable as far as difficulty and discriminative indices were concerned. Moderately easy/difficult items had maximal discriminative ability. Too easy and too difficult items gave poor discrimination index. Negative discrimination was observed in only 4% of the items indicating faulty items or incorrect keys.

Assessment of cardiovascular response to treadmill exercise in normal healthy Indian adolescents.

The study aims to assess the cardiovascular response to treadmill exercise test in healthy Indian adolescents. A group of 50 healthy adolescents took part in the study. Cardiovascular response was assessed by using treadmill exercise test as per Bruce protocol. Pulse rate, blood pressure and ECG were recorded before, during and after undertaking the treadmill test. Mean age and body mass index (BMI) were 18.7±0.51 yrs. and 21.4±3.44 kg/m2 respectively. Karl Pearson Correlation analysis showed highly significant negative correlation between BMI and exercise time (r = –0.598, P<0.001) and between resting DBP and Exercise Time (r = –0.424, P<0.002). While BMI and DBP showed highly significant positive correlation (r = 0.463, P<0.001). During exercise pulse and SBP rose and DBP fell. SBP rose from mean 122 to 175 (rise by 53 mm of Hg) and DBP fell from mean 78 to 65 (fall by 13 mm of Hg). One min recovery pulse was 156 indicating 22% fall from target heart rate. All the parameters returned to near resting value at 6 min recovery. In 30% students DBP showed exaggerated response i.e. rise during exercise. These students had more BMI and higher resting DBP as compared to other students, which could be the reason for exaggerated response in these participants. In ECG there were no significant ST/T changes during exercise or recovery period. This study provides normal data for small sample of healthy Indian adolescents when subjected to treadmill exercise test.