Statistics

Question 1

What do the bottom and top represent on the box-and-whisker plot?

Answer 1

Lower and upper quartile

Question 2

What type of variable is BMI ?

Answer 2

Continuous

Question 3

How to calculate standard error of the mean?

Answer 3

SEM = SD/√n

Question 4

In statistics population consists of

Answer 4

all subjects or objects whose characteristics are being studied

Question 5

for a negatively skewed data, mean will be

Answer 5

mean < median < mode

Question 6

for a Postively skewed data, mean will be

Answer 6

mean > median > mode

Question 7

Axises of ROC curve

Answer 7

Sensitivity/ (1-Specificty)

Question 8

Standard deviation:

Answer 8

Square root of Variance

Question 9

The ability of a test to correctly identify those who have the disease

Answer 9

Sensitivity

Question 10

The proportion of well people who are correctly classified by the screening test as negative

Answer 10

Specificity

Question 11

The proportion of people with a positive screening test who are diseased.

Answer 11

Positive Predictive value (PPV)

Question 12

The proportion of people with a negative screening test who are well.

Answer 12

Negative predictive value (PPV)

Question 13

Formula of PPV

Answer 13

All the positives

TP/TP+FP

Question 14

Formula of NPV

Answer 14

All the Negatives

TN/TN+FN

Question 15

Formula of sensitivity

Answer 15

TP/TP+FN

Question 16

Formula of Specificity

Answer 16

TN/TN+FP

Question 17

to know the number of occurrences of an event at any given interval.

Answer 17

Poisson Distribution

Question 18

What is Variance?

Answer 18

measures the degree of spread (dispersion) in a variables value
FORMULA: V= ( SD2)

Question 19

Standard Deviation

Answer 19

measure of how spread out the numbers are from the mean

FORMULA: SD = √ Variance

Question 20

Interquartile Range

Answer 20

dividing data set into quartiles and getting the midspread or middle 50%

FORMULA : IQR= Q3-Q1

Question 21

Standard error of the mean SEM:

Answer 21

is an estimate of how far the sample mean is likely to be from the population mean
FORMULA: SEM = SD/ √n

Question 22

Significant level α

Answer 22

is the probability of the study rejecting the null hypothesis, given that the null-hypothesis is true.
Significance level is set at α= 0.05 or 5%

Question 23

Significant P value: Probability value (probability of chance)

Answer 23

any number between 0 to 1

the lower the p value the more statistically significant the study is.

Question 24

Low p-value < 0.05 indicates

Answer 24

strong evidence against the null hypothesis. So your study can REJECT the null hypothesis.

Question 25

High p- value >0.05 indicates

Answer 25

weak evidence against the null hypothesis. So your study FAILS to REJECT and thus ACCEPTS the null hypothesis.

Question 26

FORMULA of Confidence interval :

Answer 26

CI= Mean +/-multiplier x SEM

Question 27

the value of multiplier for confidence intervals

Answer 27

90% –> 1.65
95% –> 2
98% –> 2.33
99% –> 2.58

Question 28

Which study is most appropriate to assess a prognosis of a disease?

Answer 28

Cohort study

Question 29

Which study is most appropriate to assess the efficacy of a new medication

Answer 29

Randomized clinical trials

Question 30

Which studies Involves analysis of data for a population at one specific point in time?

Answer 30

Cross sectional

Question 31

The hypothesis that researchers try to prove

Answer 31

alternative hypothesis

Question 32

The hypothesis that researchers try to disprove

Answer 32

null hypothesis

Question 33

Which drug trial phase primarily assesses the safety of a drug?

Answer 33

Phase 1

Question 34

What is Evidence based medicine?

Answer 34

use current experimental evidences to treat individual patients

Question 35

Increasing sample size will

Answer 35

decrease type 2 errors and increase power of the results.

Question 36

Which study is most appropriate to assess a diagnostic test?

Answer 36

Cross Sectional Analysis