Biostatistics I

Question 1

Systematic reviews and meta-analysis have the most _____ ____, in other words, you can trust the most. Next down the list is ____ _____ trials. Then ____ studies. Then ____ ____ studies.

Answer 1

Methodological rigor
Randomized controlled
Cohort
Case control

Question 2

_____ _____ are factors that increase a persons risk for a disease.

Answer 2

Risk factors

Question 3

What is a risk factor for cholera?
What is a risk factor for skin cancer?
What is a risk factor for heart disease?

Answer 3

Contaminated water
UV rays
High blood pressure

Question 4

Define incidence
Define incidence rate

Answer 4

The number of new cases of the disease for a population.
Number of new cases divided by a specific time frame.

Question 5

_____ _____ is the probability of encountering an event. It is the same as the incidence rate of the event in a particular group.

Answer 5

Absolute risk

Question 6

_____ ____ measures the excess risk accounted for by exposure to a particular risk factor. This is calculated by subtracting the ____ ____ in the two populations.

Answer 6

Attributable risk

Question 7

Attributable risk calculation:
Lifetime incidence (risk) of colon cancer with lynch = 80%
Lifetime incidence (risk) of colon cancer without lynch = 5%

Answer 7

Attributable risk = 80% - 5% = 75%

Question 8

Relative risk (risk ratio) is the risk for a condition in one population ____ to another.

In other words, people with Lynch syndrome are 16 times more likely to develop colon cancer, then someone without lynch syndrome.

Answer 8

Compared

Example: lifetime incidence of colon cancer with Lynch = 80%
Lifetime incidence of colon cancer without lynch = 5%
Relative risk = 80/5 = 16

Question 9

What is the 5 year incidence of MI in those with hypertension?

Answer 9

60/1000 = 6%

Question 10

Answer 10

73 / (73 + 915) = 7.4%

Question 11

What is the relative risk of people with hypertension for developing an MI?

Answer 11

3

Question 12

The portion of the risk of a disease in the population that is due to exposure to a risk is ___ ____ ____.

Answer 12

Attributable risk percent

Question 13

What is the attributable risk percent using this table:

Answer 13

100 ((0.06- 0.02) / 0.06) = 66%

Question 14

Answer 14

Question 15

Answer 15

Question 16

_____ all current cases are all cases at a given time, new and old. It is dependent on incidence, and their average duration of the disease from time to diagnosis to time of cure or death.

Answer 16

Prevalence.

Question 17

Incidence and prevalence both measure the ____ ____ of a disease.

Answer 17

Morbidity rate

Question 18

The ____ ____ ____ is a measure of severity of a disease. The number of fatal cases, divided by the total number of people with the disease.

Answer 18

The case fatality rate

Question 19

_______ is used to determine if there are significant differences between the means of two groups.

Answer 19

T-test

Question 20

_____ is used to determine whether there are significant differences between the means of two or more independent groups

Answer 20

ANOVA

Question 21

_____ is reported in studies the compare the means of two or more groups.

Answer 21

P-value

Question 22

If the P value is <.04, this indicates that there is a less than ____ percent chance that the difference that they found is due to chance alone.

Answer 22

4

Question 23

P values of _____ are considered statistically significant

Answer 23

<0.05

Question 24

____ ____ indicates a range of values within which we believe that the true value lies along with the level of certainty.

Answer 24

Confidence intervals

Question 25

95% Cl: 3.0 to 3.9 means….

Answer 25

If this study were repeated, we would estimate that 95% of the time the results would fall between 3 and 3.9 times as likely to have an injury for example.

Question 26

If the confidence interval does not include one, this means that the results are ____ ___ in other words the P value is <.05
If the confidence interval includes one, the P value is >.05 and not ____ ____.

Answer 26

Statistically significant
Statistically significant

Question 27

Answer 27