Final answer:
Using the range rule of thumb with the given mean and standard deviation, significantly low values are 57.6 beats per minute or lower, and significantly high values are 105.2 beats per minute or higher. A pulse rate of 55.2 beats per minute is considered significantly low. so, option c is the correct answer.
Step-by-step explanation:
The question is about using the range rule of thumb to identify the limits separating significantly low or high pulse rates based on the provided mean and standard deviation. According to the range rule of thumb, the limits can be calculated as the mean plus or minus two times the standard deviation. In this case, to find the limits, we perform the following calculations:
- Significantly low limit = mean - (2 × standard deviation) = 81.4 - (2 × 11.9) = 57.6 bpm
- Significantly high limit = mean + (2 × standard deviation) = 81.4 + (2 × 11.9) = 105.2 bpm
So, significantly low values are 57.6 beats per minute or lower and significantly high values are 105.2 beats per minute or higher. As a pulse rate of 55.2 beats per minute is below the significantly low limit, it is considered significantly low.
The range rule of thumb states that within one standard deviation of the mean, approximately 68% of the data should fall. To identify significantly low or high values, we can use the mean minus the product of the standard deviation and 1.5 and the mean plus the product of the standard deviation and 1.5, respectively.
For this particular group of test subjects, the significantly low values would be 81.4 - (11.9 * 1.5) = 62.25 beats per minute or lower. The significantly high values would be 81.4 + (11.9 * 1.5) = 100.55 beats per minute or higher.
A pulse rate of 55.2 beats per minute is significantly low because it falls below the lower limit of 62.25 beats per minute.