Statistical Analysis of Mental Stress During Oral Presentation

An oral presentation is a key stressor in a work environment. High levels of stress might abruptly decrease the quality and quantity of information that needs to be delivered to the audience. So it is important to analyze the person’s stress levels and regulate their stress condition for a better result in their delivery of a speech. Heart Rate Variability (HRV) derived from Electrocardiogram (ECG) is a well-established measure for stress analysis of an individual. To analyse stress, ECG data were collected during an oral presentation from 44 subjects. Frequency domain spectral analysis was done to classify the stress regions. The ratio of the Low Frequency to High Frequency (LF/HF) parameter, a widely accepted method of HRV analysis, was calculated every 5 minutes throughout the entire data. The ECG data were collected for 8 hours during the day. The primary statistical analysis was done to understand the patterns and changes that gets reflected due to this activity. 4:30 to 5:30 PM was the time in which the oral presentation was made each ranging from 15 to 25 minutes. Statistical analysis was done for comparison between the oral presentation period and the other time periods. An increase in the LF/HF ratio was observed during the oral presentation. Variations in the median and standard deviation were observed in both data sets. Analysis of variance was done to understand the variation in the subgroup of the data. A comparison box and whisker plot representation is done to show the distribution, its central value and variability between male and female subjects. The distribution was found to be wider for male subjects compared to female subjects. The standard deviation of LF/HF ratio during the oral presentation was significantly higher than during normal working hours. Also, subjects were requested to answer a short questionnaire to understand the cause of mental stress and the results were discussed.