<prompt> Test used to assess quantitative observations before and after an intervention ?Unpaired T-testPaired T-testChi-square testFisher-T-test  <response>: Ans. is b i.e., Paired T-test Student t-test Small samples do not follow normal distribution as large ones do. To overcome this problem t test was devised by W.S. Cassette whose pen name was student and hence this test was called student T test. Application of test : It is applied to find the significance of difference between two means, when sample size is less than 30. It is applied on a standard population either as : 1. Unpaired e test : Applied when data is unpaired, i.e. when separate observations are made on inidividuals of two separate groups, and these need to be compared : Null hypothesis is assumed Observed diference between means of two samples is found. Standard error or difference between two means is calculated. t value is estimated. This is the ratio between points 2 and 3. Degrees of freedom are next calculated Calculated values are compared with the table values at the calculated degree of freedom option d P values are obtained and if it is more than 0.05, it has no significance. 2. Paired test : Is applied to paired data, when each individual gives a pair of observations such as : when observations are made before and after the play of a factor e.g. pulse rate before and after a drug. Fuher, it proceeds similar to the unpaired test. 