When different interviewers are used in a pretest from those used in the posttest and this produces different results in the study, this is an example of a
1). History effect
2). Mortality effect
3). Instrumentation effect
4). Cohort effect
1. which of the following is not needed in experimental research
2. Which of the following is an unstructured tool?
3. Action research is a type of ........
4. Who of the following has edited a survey of educational research ?
6. Which of the following is NOT an example of quantitative variable?
7. The chief characteristics of sampling is-
9. Which of the following is a type of criterion-related validity evidence?