STATISTICS UNLOCKING THE POWER OF
DATA COMPREHENSIVE EXAMINATION
TEST COMPLETE QUESTIONS AND
CORRECT ANSWERS
●● What are the two possibilities when you reject the null hypothesis?
Answer: 1. The null is false and you correctly found significance. 2. The
null is true and you incorrectly claimed significance (Type I error).
●● What happens when you fail to reject the null hypothesis?
Answer: 1. The null is true and you correctly found no significant effect.
2. The null is false and you did not reject it (Type II error).
●● What is a Type I error?
Answer: Claiming a significant difference exists when the null
hypothesis is true.
●● What is a Type II error?
Answer: Failing to reject the null hypothesis when it is false.
●● What is the minimum power desired for any statistical test?
Answer: 80% power.
,●● What is a priori power?
Answer: Power calculated before collecting data, typically involving
expected effect size and sample size.
●● What is post hoc power?
Answer: Power calculated after the statistical result, usually if it is not
significant.
●● How can power be increased?
Answer: 1. Decrease spread. 2. Increase group differences. 3. Increase
sample size. 4. Increase the alpha cut off (not recommended).
●● What does decreasing spread do to power?
Answer: It reduces noise in the data, decreasing overlap between
distributions and increasing power.
●● How does increasing group differences affect power?
Answer: It lessens the overlap between groups, thereby increasing
power.
●● What effect does increasing sample size have on power?
Answer: It makes the sampling distribution thinner, reducing overlap
and increasing power.
, ●● Why is increasing the alpha level considered cheating?
Answer: It lowers the threshold for significance, increasing the Type I
error rate.
●● What is the effect of a power of 0.40 in a study?
Answer: It indicates a 40% chance of finding a significant result if one
exists, which is considered poor power.
●● What does it mean if power is less than 80%?
Answer: There is a high likelihood of failing to detect a true effect.
●● What is the relationship between statistical power and confidence in
findings?
Answer: Higher power results in more confidence that there is a true
effect, while lower power indicates inconclusive results.
●● What is the critical cut off in hypothesis testing?
Answer: The threshold beyond which the null hypothesis is rejected.
●● What is the role of literature convergence in evaluating statistical
significance?
Answer: It helps determine if findings make sense and if they can be
replicated.
DATA COMPREHENSIVE EXAMINATION
TEST COMPLETE QUESTIONS AND
CORRECT ANSWERS
●● What are the two possibilities when you reject the null hypothesis?
Answer: 1. The null is false and you correctly found significance. 2. The
null is true and you incorrectly claimed significance (Type I error).
●● What happens when you fail to reject the null hypothesis?
Answer: 1. The null is true and you correctly found no significant effect.
2. The null is false and you did not reject it (Type II error).
●● What is a Type I error?
Answer: Claiming a significant difference exists when the null
hypothesis is true.
●● What is a Type II error?
Answer: Failing to reject the null hypothesis when it is false.
●● What is the minimum power desired for any statistical test?
Answer: 80% power.
,●● What is a priori power?
Answer: Power calculated before collecting data, typically involving
expected effect size and sample size.
●● What is post hoc power?
Answer: Power calculated after the statistical result, usually if it is not
significant.
●● How can power be increased?
Answer: 1. Decrease spread. 2. Increase group differences. 3. Increase
sample size. 4. Increase the alpha cut off (not recommended).
●● What does decreasing spread do to power?
Answer: It reduces noise in the data, decreasing overlap between
distributions and increasing power.
●● How does increasing group differences affect power?
Answer: It lessens the overlap between groups, thereby increasing
power.
●● What effect does increasing sample size have on power?
Answer: It makes the sampling distribution thinner, reducing overlap
and increasing power.
, ●● Why is increasing the alpha level considered cheating?
Answer: It lowers the threshold for significance, increasing the Type I
error rate.
●● What is the effect of a power of 0.40 in a study?
Answer: It indicates a 40% chance of finding a significant result if one
exists, which is considered poor power.
●● What does it mean if power is less than 80%?
Answer: There is a high likelihood of failing to detect a true effect.
●● What is the relationship between statistical power and confidence in
findings?
Answer: Higher power results in more confidence that there is a true
effect, while lower power indicates inconclusive results.
●● What is the critical cut off in hypothesis testing?
Answer: The threshold beyond which the null hypothesis is rejected.
●● What is the role of literature convergence in evaluating statistical
significance?
Answer: It helps determine if findings make sense and if they can be
replicated.
