Answer:
Step-by-step explanation:
External validity : it is the extent to which the result of the studies can be generalised in the experimental research.
Given that ,Dr. Parrett is a sports psychologist for a large Southern university. The provost and chancellor have asked him to examine the relationship between athletic performance and academic stress at the university. The provost and chancellor have made it clear to Dr. Parrett that they want a large amount of external validity in the study. He has valid and reliable measures of both athletic performance and academic stress. He knows that he does not have the time or the money to study the entire population of interest.
As he works only for southern university , but he has to generalize the conclusion for the whole sports man., as per the external validity. It does mean that the conclusions & measures made by Dr. Parrett should hold for the universe.
1) Population of interest in his study is the related data of all sportsman in the universe.
2) He needs to concern external validity because the conclusion should not hold for specific location by affecting some extraneous variables. It should be generalised.
3) a) convinience sampme : He can collect the data related to some specific sportsman by the observation & experience as per the convinience as per the time & money consraints to avoid hurdls in future.
b) Simple random sample also he can go for to have right conclusions without replacement as it is having equal probabilities of selection.
c) As he has to draw the conclusions by measures for the whole universe , he can apply clusr sampling also to save time, money as well to have accuracy.• It is useful when: (i) A list of elements of the population is not available but it is easy to obtain a list of clusters. (ii) The cost of obtaining observations increases as the distance that separates the elements.
4) cluster sample will be the best as per the purpose & consraint of the study.
Cluster sampling is less expensive and more quick. It is more economical to observe clusters of units in a population than randomly selected units scattered over throughout the state.
Cluster Sample permits each accumulation of large samples.
The loss of precision per individual case is more than compensated for by the possibility of studying larger samples for the same cost.
Cluster sample may combine the advantages of both random sampling as well as stratified sampling.
Cluster sampling procedure enables to obtain information from one or more areas.
5) They measure concern over their grades is an observational measure.
