The sample size needed for a study increases when: a. the ...

[panfilo]

The sample size needed for a study increases when:
 
  a. the alpha level is increased from .01 to .05.
  b. the number of variables in the study increases.
  c. a one-tailed versus a two-tailed statistical test is used.
  d. the sensitivity of the instruments used is high.

Question 2

Which of the following statements is true about sampling plans?
 
  a. A probability sampling plan is a better plan than a nonprobability one.
  b. A sampling plan outlines strategies used to obtain a sample for a study.
  c. Each study has its own sampling method, unique to that project.
  d. Getting a sample that is the most representative is the ideal, not the goal, of the sampling plan.

[batool]

Answer to Question 1

ANS: B
As the number of variables under study increases, the sample size needed may increase.
The reverse of this statement is true. As the number of variables under study increases, the sample size needed may increase.
One-tailed tests do not require as large a sample as two-tailed tests. As the number of variables under study increases, the sample size needed may increase.
High sensitivity of the instruments can allow for a smaller sample size. As the number of variables under study increases, the sample size needed may increase.

Answer to Question 2

ANS: B
A sampling plan, or sampling method, defines the selection process for a study.
A probability plan is not inferior to a nonprobability plan (although the study itself might be considered in a more favorable light).
The sampling plan is not specific to any one study.
Getting a sample that is the most representative is oftentimes the goal of the sampling plan.

[panfilo]

TYSM

[raenoj]

Gracias!