In clinical and epidemiological studies research are very much interested to know the inter ?observer variation in a continuous variable or two measurement techniques Example.Measurement of blood pressure with pulse oximetry and ausculatory method or measurement of PEFR respiratory diseases by wright peak flow meter and mini wright meter in other case pulse rate of patient measure by two nurse or doctor The conventional Statistical method applied for studying the agreement between two method of measuring a continuous variable is computing the Correlation Coeffi cient (r), but many times this is misleading for this purpose.A change of scale of measurement does not alter r but affect the agreement.In order to overcome this difficulty we will apply five test and in case three will come out to be true we can say that there is good agreement exist between two rater or techniques