<prompt> Study done on a group of patients showed coefficient of variance for BP and serum creatinine to be 20 15 respectively. Inference is that -Variation in BP is more than in serum creatinineVariation in serum creatinine is more than in BPStandard deviation of BP is more than of creatinineStandard deviation of creatinine is more than of BP  <response>: Coefficient of varianceCoefficient of variance indicates how large standard deviation is relative to mean, i.e. Coefficient of variance is a relative comparison of a standard deviation to its mean. It is expressed as percentage.CV Standard deviation mean x 100For example, if the standard deviation of a sample is 8 and the sample mean is 44. The CV will be 18.2 . That means the standard deviation is 18.2 of the value of mean.Significance of coefficient of varianceCV is a measure used to Compare relative variability when the mean is different in sample to be compared or in character variables to be compared CV compares variability of two different characteristics e.g., BP, Serum creatinine, height, weight etc. in the same group of subjects. In this situation mean BP of the sample will have different value e.g., 120 and mean creatinine level will have different value e.g., 0.8 in the same group sample.CV can compare variability of the same character in two or more different groups samples. For example taking the height in a group from India and in other group from USA. Both the samples will have different mean height.In these situations, when the mean is different for characteristics to be compared, CV is used to compare the relative variability.Taking the example of given question :CV for BP in a group is 20.CV for serum creatinine in the same group is 15.That means for BP, standard deviation is 20 of the mean; and for creatinine, standard deviation is 15 of the mean.It has already been explained that standard deviation is measure of variation deviation. Therefore, in the given question variability is more in BP than in serum creatinine value.So, Coefficient of variance is used to compare variability of two different characteristic in same group or to compare variability of the same character in different groups as the mean is different in both these situations.Since coefficient of variance is a ratio, it has no units of measurement dimensionless. It can be used to compare variability irrespective of the units of measurement used in two or more different group.For exampleIt can compare variability if height measures as cm in one group inches in another group.About option c dWe cannot comment on standard deviation by knowing just only the coefficient of variance because we dont know the mean BP and mean creatinine level of the sample group In three related variables Here CV, SD mean you must know the value of two variables to comment on value of the third one.However, in this question we can say that the standard deviation relative to mean is large for BP than for serum creatinine.So, we cannot comment on absolute value of standard deviation whether SD of BP is more or SD of creatinine is more, But we can comment on standard deviation relative to mean. 