In what sort of sampling does the researcher divide the population into separate groups called strata, then draw a probability sample from each group?
Which type of random sample is used for selecting a sample from one strata of society?
Which type of random sample can be used to study the level of qualifications in a society divided into lower class, middle class and upper class?
Which type of random sample should be used to determine the subject preferences of a group of 400 students given the ratio of males to females is ?
Which of the following data sets is suitable to examine the blood type of a patient?