For estimating a population mean by simple random sampling, with the population variability unchanged, which decision tends to decrease the standard error of the sample mean?
Increasing the random sample size
Under simple random sampling, the standard error decreases as sample size increases, with population variability fixed. For a large population it is approximately the population standard deviation divided by the square root of the sample size. Reordering or rounding the data report does not reduce sampling variability.
Important Questions from Components of Research - Teaching
An investigator wants to conduct a study on orthopaedically handicapped children. The type of sampling to be used would be
Match each characteristic in List I with the validity evidence in List II.
List I: (a) Test scores predict later performance on an external criterion; (b) Scores support interpretation in terms of a theoretical psychological construct; (c) Test content represents the intended knowledge domain; (d) Scores relate to an appropriate external criterion measured at about the same time.
List II: (i) Content validity; (ii) Predictive validity; (iii) Concurrent validity; (iv) Construct validity.The element that differentiates between stratified and quota sampling techniques is
If a sample survey of the same 100 households is conducted in a particular village, annually for five years, the data so collected will be described as :
- Consider the following assertion and reason.
Assertion A: A concurrent validity coefficient can exceed a predictive validity coefficient when intervening changes weaken the relationship with the later criterion.
Choose the most appropriate answer.
Reason R: A higher validity coefficient alone does not establish that a test is more suitable for a particular purpose.
