2. Basic Statistics

Significant

Is a p < 0.05 significant or not significant?

Not significant

Is a p > 0.05 significant or not significant?

F

T/F: The amount over or under 0.05 that the p-value is provides insight into the importance of the p-value.

Strong enough evidence against the null hypothesis that you can reject the null hypothesis and accept your hypothesis.

What does a small p-value indicate?

Weak evidence against the null hypothesis that you fail to reject the null hypothesis, but you CANNOT say that the null hypothesis is true.

What does a large p-value indicate?

F

T/F: You can base clinical decision only on a p-value.

F

T/F: A p-value measures the size of an effect or the importance of a result.

T

T/F: A p-value does not measure probability that the null hypothesis is true.

T

T/F: A p-value is not the error rate for the study.

Type 2 error

What error type if a false negative?

Type 1 error

What error type is a false positive?

Type 2 error (FN)

What type of error is beta?

Type 1 error (FP)

What type of error is alpha?

Type 1 (alpha, FP)

Which error type do we NOT want to make — type 1 or type 2?

p = 0.05

What is the alpha set at?

20%

What is the beta set at?

Power = 1 - beta

(80% = 1 - 20%)

How can you calculate the power?

T

T/F: Generally, we are less worried about type 2 errors.

- Sample size

- Variation and precision of the study data (instruments that you use)

What influences the width of the range of the CI?

Confidence interval

What am I describing?

- Provides information about the range of the statistical parameter of interest.

Confidence interval

What provides more information about the direction and magnitude of the effect measured in the study?

A = not statistically significant, not clinically relevant

B = statistically significant and clinically relevant

C = statistically significant, but not clinical relevant

D = not statistically significant, clinically relevant

Gold standard

What am I describing?

- Chosen by mortals

- Imperfect

- Applicable only in the "moment"

The gold standard

All estimates of Sn, Sp, PPV, NPV, RR, and OR are made relative to what?