Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biostatistics > Past Papers > Flashcards

Past Papers Flashcards

1
Q

Which of the following is a measure of spread?

Median.

Mean.

Mode.

Range.

A

Range

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

7)We would like to compare the efficacy of an original drug and generic one. Choose the correct null hypothesis.

  • The efficacy of the generic drug is not significantly different from the original.
  • The difference between the efficacy of the two drugs is not because of incidence.
  • The efficacy of the generic drug is not identical to that of the original one.
  • Incidence has no role in the efficacy difference between the two drugs.
A

The efficacy of the generic drug is not significantly different from the original.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

6) Choose the right statement on type II error.

  • The null hypothesis is accepted, although it is false.
  • Gives the error of wrong decision.
  • The alternative hypothesis is accepted, although it is false.
A

The null hypothesis is accepted, although it is false.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

8) Pick the correct statement.

  • The condition of t-test for one sample is that the variable to be analyzed follows normal distribution.
  • The condition of t-test for one sample is that the standard deviation is one.
  • T-test can only be applied for variables following standard normal distribution.
  • The condition of t-test for one sample is that the variable to be analyzed follows Student’s t-distribution
A

The condition of the t-test for one sample is that the variable to be analyzed follows normal distribution.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

9) In which case should one reject null hypothesis?

  • If the absolute value of the statistical parameter calculated from the sample is greater than the absolute value of the critical statistical parameter.
  • If the p-value calculated from the sample is greater than the critical p-value.
  • If the p-value calculated from the sample is greater than 5%.
  • If the absolute value of the statistical parameter calculated from the sample is greater than 5%.
A

If the absolute value of the statistical parameter calculated from the sample is greater than the absolute value of the critical statistical parameter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

10) We are executing the two tailed t-test. Choose the possible outcome.

  • t=0 and p=1.
  • t=100 and p=1.
  • t=0 and p=0.
  • p=0 and t=1.
A

t= 0 and p= 1.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

11) What does the term “tied rank” stand for in statistics?

  • Identical ranks that are assigned to values of equal magnitude.
  • Ranks that are assigned to data in a two-sample t-test for data pairs.
  • Ranks not exchangeable within a sample
  • Ranks not exchangeable between samples.
A

Identical ranks that are assigned to values of equal magnitude.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

12) Choose the right statement. The y-axis intercept of the regression line…

…cannot be zero.

…cannot be more than one.

…cannot be less than negative one.

…can be any real number.

A

…can be any real number.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

13) Choose the right statement.

  • If the alpha error (type I error) is one, the beta error (type II error) is 0.
  • The alpha error (type I error) is always less than the level of significance.
  • The beta error (type II error) can never be estimated.
  • Although the value of the beta error can not be determined exaclty, we know that it is less than the alpha error (type I error).
A

The alpha error (type I error) is always less than the level of significance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

14) When is ANOVA applicable?

  • If more than half of the samples to be compared are normally distributed.
  • If the variance of the samples is equal and all samples are normally distributed.
  • If the samples to be compared are independent and normally distributed.
  • When it yields less alpha and beta error than a series of paired t-tests.
A
  • If the variance of the samples is equal and all samples are normally distributed.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

15) Which is correct?

The Wilcoxon sign test can be used for categorical variables.

The Wilcoxon signed ranks test is based on the differences of the original values.

The wilcoxon signed ranks test is based on the original values.

The Wilcoxon sign test can be used both for categorical and for numerical variables.

A

The Wilcoxon signed ranks test is based on the differences of the original values.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

16) Which statement is correct about the relationship between A and B, if P(AB)= P(A) x P(B)?

  • It is true only if A and B are representative events.
  • This equation is true if A and B = independent.
  • If A and B are random events, the claim is correct.
  • It is correct for any A and B events.
A

This eqaution is true if A and B are independent.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

17) A homogeneity test should be performed. Which method should be used?

  • Mann-Whitney test.
  • Sample t-test.
  • Two sample t-test.
  • Chi-square test.
A

Chi-square test.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

18) Which is correct?

…approximately equal.

The t-test may be applied only for variables with standard normal distribution.

In a correlation t-test, the two variables are normally distributed.

Condition for the sample t-test: the test variables must be normally distributed.

A

Conditions for the sample t-test: the tested variables must be normally distributed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

19) When testing an anti-cancer drug, a paired t-test results in the value t=0. what conclusions can we draw this from?

Because t=0, and therefore also p=0, the drug is effective.

The null hypothesis must be accepted, ex: the drug is effective.

The null hypothesis should be rejected, so there is no effect.

we measured prctically the same before and after the treatment.

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

20) which is correct for the correlation coefficient?

If the correlation coefficient is zero, the is no connection between the two variables.

If the null hypothesis is correct, the correlation coefficient is equal to one.

It is a measure of the relationship between two numerical varaiables.

(*If r > 5, then caused the change of a variable change the other one another - Idk what this is suppose to mean(?))

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

22) How large is the degree of freedom in a chi-square homogeneity test if the issue is examined, that the distribution of medical or health care professional even in 5 hospitals?

10

4

5

1

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

23) What distribution density function is not symmetrical?

The distribution density function of a t-distribution with degree of freedom n.

The distribution density function of the chi-2 distribution.

The distribution density function of a Gaussian distribution.

The distribution density function of a uniform distribution.

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

24) What is the probability of a certain event

1

0.5

0

infinite

A

1

20
Q

26) How large is the degree of freedom of the t-test for correlation coefficient when the sample size is equal to 29?

56

28

27

A

27

degree of freedom = 29-2

21
Q

30) Which parameter is not location parameter?

Median

Arithmetic mean

Mode

Variance

A
22
Q

37) We studied a numerical, continuous variable in two samples with the same amount. The two 37 groups are normally distributed and the variance can be assumed to be equal. Can a Mann- Whitney U-test be used in this case?

No. Nonparametric test should be applied only to non-numeric data.

No. You absolutely must use a t-test because the characteristics of the samples meet the requirements of the t-tests.

No. We must perform an Kruskal-Wallis test.

A
23
Q

38) We want to test with a t-test whether the 28 pateints in the hematology ward have the same red cells count as the 28 patients in the contagious ward. What is the number of degrees of freedom?

29

27

54

14

A
24
Q

39) What is the right decision, if the calculated sample p-value is 0.045, and the critical p-value is 0.114?

The alternative hypothesis is rejected.

The null hypothesis is accepted.

The null hypothesis is rejected.

Neither the null hypothesis nor the alternative hypothesis can be accepted

A
25
Q

43) A test for homogenity is to be conducted. Which method shall be used?

Students t-test for two samples.

Mann- Whitney U test.

Chi-square test.

Student’s t-test for one sample.

A
26
Q

44) The sample p-value calculated during a Wilcoxon test is 0.482. The critical p-value is 5%. Choose the correct statement.

The difference between the medians is significantly in 52% of all cases.

The null hypothesis is rejected, i.e. a significant difference can be assumed between the values measured before and after the treatment.

There is no significant difference between the medians i the 52% of all cases.

The null hypothesis is accepted , i.e. there is no significant difference between the values measured before and after the treatment.

A
27
Q

45) We are studying a numerical, continous variable in two groups having equal number of elements. Both groups show normal distribution, the variances can be considered equal. Can we use Mann -Whitney U test in this case.

No , we cannot, in the described conditions we have to use Kruskal -Wallis test.

No, we cannot we have to use t-test, since the conditions fulfill the requirements for the t-test.

Yes, we can because the sample fulfills the preconditions of the test.

A
28
Q

46)In which case is the following eqn valid: p(A+B) = p(A)+ p(B).

  • If “A” and “B” are mutually exclusive events.
  • If “A” and “B” are independent events.
  • For any “A” and “B” events.
  • If “A” and “B” are dependent events.
A

If “A” and “B” are mutually exclusive events.

29
Q

47) What is the number of degrees of freedom in case of a chi-square test for homogenity, if we study whether the distribution of a male and female patients in our 6 hospitals is uniform?

1

5

10

4

A
30
Q

48) What is the number of degrees of freedom in case of a correltaion t-test, if the sample size is 16?

30

15

14

16

A
31
Q

53) The pain killer effect of Aspirin and new drug called “Novanopain” is compared. Choose the optimal test method.

Examining the correlation between the two main groups with t-test.

Two samplet-test, since we wanted to compare two independent groups.

Mann-Whitney U-test.

Simply compare the confidenec intervals.

A

Two sample t-test, since we want to compare two independent groups.

Mann-Whitney U-test.

32
Q
A
33
Q
A
34
Q

50) We would like to compare the effcicay of an origional frug and a generic one. choose the correct null hypothesis.

The difference between the efficacy of the two drugs is not because of incidence.

Incidence has no role in the efficacy difference between the two drugs.

The efficacy of the generic drig is not identical to that of the original one.

The efficacy of the generic drug is not significantly different from the original.

A

The efficacy of the generic drug is not signicicantly different from the original.

35
Q

Choose the right statement.

The slope of the regression line can be any real number.

The slope of the regression line cannot be zero.

The slope of the regression line cannot be more than one.

The slope of the regression line cannot be less than negative one

A

The slope of the regression line can be any real number.

36
Q

51) The probability of occurrence of an event is 0.18. What is the probability that it does not occur?
- 0.82
0. 82
0. 09

0

A

0.82

37
Q

What is the number of degrees of freedom in case of a correlation t-test, if the sample size is 23?

21

22

44

23

A

correlation t-test: deg.free (n-2)

23-2 =21

38
Q

Choose the right statement on type error II.

  • The null hypothesis is accepted, although it is false.
  • Gives the error of the right decision.
  • Gives the error of the wrong decision.
  • The alternative hypothesis is accepted, although it is false.
A

The null hypothesis is accepted, alhough it is false.

39
Q

We would like to compare the efficacy of an original drug and generic one. Choose the correct null hypothesis.

The efficacy of the generic drug is not significantly different from the original.

The difference between the efficacy of the two drugs is not because of incidence.

The efficacy of the generic is not identical to that of the original one.

Incidence has no role in the efficacy difference between the two drugs.

A

The efficacy of the generic drug is not significantly different from the original.

40
Q

What is the right decision, if the calculated sample p-value is 0,072, and the critical p-value is 0,114?

The null hypothesis is rejected.

Neither the null nor the alternative hypothesis can be accpeted.

The alternative hypothesis is rejected.

The null hypothesis is accepted.

A

The null hypothesis is rejected.

41
Q

The correlation coefficient is close to one if…

…the relationship between the variables is not significant.

…the relationship between the variables is function-like.

…the relationship between the variables is linear.

…the relationship between the variables is linear with positive increment.

A
42
Q

Choose the right statements. The y axiz intercept of the regression line…

….cannot be zero.

…cannot be less than negative one.

…cannot be more than one.

…can be any real number.

A
43
Q

In which case should one reject the null hypothesis?

  • If the p-value calculated from the sample is greater than 5%.
  • If the p-value calculated from the sample is greater than the critical p-value.
  • If the absolute value of the statistical parameter calculated from the sample is greater than the absolute value of the critical statistical parameter.
  • If the absolute value of the statistical parameter calculated from the sample is greater than 5%.
A
  • If the absolute value of the statistical parameter calculated from the sample is greater than the absolute value of the critical statistical parameter.
44
Q

What is the number of degrees of freedom in case of a correlation t-test, if the sample size is 15?

28

13

15

14

A

13

45
Q

What is the right decision, if the calculated sample p-value is 0,072, and the critical p-value is 0,1?

The null hypothesis is rejected.

The alternative hypothesis is rejected.

The null hypothesis is accepted.

Neither the null nor the alternative hypothesis can be accpeted.

A
46
Q

pick the correct statement.

the condition of t-test for one sample is that the standard deviation is one.

T-test can only be applied for variable following standard normal distribution.

The condition of the t-test for one sample is that the variable to be analyzed follows normal distribution.

The condition of t -test for one sample is that the variable to be analyzed follows student’s t distribution.

A

The condition of t-test for one sample is that the variable to be analyzed folows normal distribution

Biostatistics (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions