Which of the following is a reason why we may NOT find a significant difference between two groups? ...

Which of the following is a reason why we may NOT find a significant difference between two groups?
 
  a. The sample size was too small.
  b. The true mean difference between the groups was too small.
  c. The variability between the groups was too large.
  d. all of the above

Question 2

Before running an experiment, we decide to calculate power. We find that the power equals .95. What conclusion can be made?
 
  a. We should not run the experiment.
  b. 95 of the time, we will not find a significant result.
  c. We should run the experiment.
  d. We need 95 subjects to find a significant result.

Question 3

A harmonic mean can be used to calculate the mean sample size for unequal sample sizes. For _______ the values of k would equal _______.
 
  a. related means t test; 3
  b. related means t test; 2
  c. independent samples t test; 3
  d. independent samples t test; 2