to check or to prove one of the previous studies. An example of this can be a teacher s leadership style. Suppose that according to one of the studies a biology teacher was successful by using a particular leadership style. The next researcher can use this study as a foundation for his or her study. And finally there will be several studies proving that biology teachers in a particular situations or cases can be successful by using a special leadership style . The biggest quantitative research which can be done is the one where the whole population will be covered. But practically it is hardly possible. That is why there are two common ways: to identify a target population or accessible population. In the target special group of people can be involved, such as all biology teachers in New Jersey, or special teachers in Tampere. The idea of ​​this target group that it sounds not very huge, but the outcome can be applicable for the same group of people but wider. Another way is accessible population, the research done in this way can cover larger group of people, such as all school-leavers in Kuopio. Of course practically it is not possible to involve all the school-leavers, but a researcher has to choose those schools which are close the place where he or she lives and some neigbouring. Then some generalization must be done. First the results from the participants who were involved will be generalized to the accessible population and then it can be generalized to the target group, this process is called inferential leaps. And these generalizations can be done much easier if participants were chosen randomly, if everybody was equal and could participate. But if there was a selection of people for the research, then the researcher has to prove that any generalization is possible, to show that some similarities between participants and accessible population and then target population can be found. Choosing participants for the sample randomly is more challenging than a systematic way. Random selection takes more time, it can be done either through a table, where each possible participant has it is own number or with a help of computer programme. While in the systematic way more logic can be found, such as every tenth or every 37 th student or a teacher.idea of choosing a sample in qualitative research is different from a quantitative one, the most common sampling is a purposeful one, within which Patton identifies 15 strategies.
. Extreme or deviant case sampling is concentrated on unusual or strange cases. These example can give som...
