Statistics

Question 1

Define sensitivity

Answer 1

% of patients WITH disease that will test POSITIVE
low sensitivity= lots of false neg

Question 2

Define specificity

Answer 2

% of patients WITHOUT dz that will test negative
low specificity = lots of false positives

Question 3

What is the positive predictive value?

Answer 3

Likelihood patient with positive result has disease
True positives / true and false positives = PPV

Question 4

What is the negative predictive value?

Answer 4

Likelihood patient with negative result does not have disease

Question 5

What is the positive likelihood ratio?

Answer 5

Sensitivity /1-Specificity

Question 6

What is the negative likelihood ratio?

Answer 6

1-sensitivity/specificity

Question 7

Define descriptive statistics

Answer 7

Presenting, organizing, and summarizing data
Ex: range, standard deviation

Question 8

Define inferential statistics

Answer 8

Drawing conclusions about a population based on data observed in a sample
Ex: Standard error, confidence interval

Question 9

What is a null hypothesis?

Answer 9

No significant difference between specified populations, any observed difference being due to sampling or experimental error

If p value is <0.05 = reject null hypothesis

Question 10

What is the p value?

Answer 10

Probability of finding the observed or more extreme results when the null hypothesis is true

Question 11

What is a type I error?

Answer 11

Conclude that the difference between the groups is statistically significant and reject the null hypothesis, when in reality, the groups are the same. FALSE POSITIVE RESULT

Question 12

What is a type II error?

Answer 12

Conclude that there is no statistically significant difference, when in reality there is a difference between the groups and the null hypothesis is indeed false. FALSE NEGATIVE RESULT
Ex: population not big enough