EPD711S - EPIDEMIOLOGY 3 - 1ST OPP - JUNE 2022 :: NUST past examination papers between 2020 and 2024

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EPD711S - EPIDEMIOLOGY 3 - 1ST OPP - JUNE 2022

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EPD711S - EPIDEMIOLOGY 3 - 1ST OPP - JUNE 2022

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nAm I BIA u n IVE RS ITV

OF SCIEnCE Ano TECHnOLOGY

FACULTYOF HEALTH,APPLIEDSCIENCESAND NATURAL RESOURCES

DEPARTMENT OF HEALTHSCIENCES

QUALIFICATIONS:BACHELOROF ENVIRONMENTALHEALTHSCIENCESB, ACHELOROF SCIENCEIN

HEALTHINFORMATIONSYSTEMSMANAGEMENT, BACHELOROF HUMAN NUTRITION

QUALIFICATION CODE: 08BOHS, 07BHIS,

08BOHN

LEVEL: 7

COURSECODE: EPD711S

COURSENAME: EPIDEMIOLOGY3

SESSION:

JUNE 2022

PAPER:

THEORY

DURATION: 3 HOURS

MARKS:

100

FIRSTOPPORTUNITY EXAMINATION QUESTION PAPER

EXAMINER(S) DR LARAIAKU-AKAI

MODERATOR: DR ROSWITHAMAHALIE

INSTRUCTIONS

1. Answer ALL the questions.

2. Write clearly and neatly in the spaces provided.

PERMISSIBLEMATERIALS

1. Scientific calculator

2. Statistical tables (attached)

THIS QUESTION PAPERCONSISTSOF 9 PAGES(including this front page)

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Question 1

Select the most appropriate answer from the options provided.

1.1 Which of the following can be obtained from retrospective studies:

a) Attributable risk

b) Prevalence rate

Relative risk

d) Odd's ratio

(20 marks)

(1)

1.2 These are all discrete variables except:

a) Cars in the garage

b) Boys in the classroom

c) Height in metres

d) Computer hardware delivered

(1)

1.3 The total number of cases of a disease at a given point in time in a given population is:

a) Incidence

b) Prevalence

Epidemiology

d) Attack rate

(1)

1.4. Seasonal variation of a disease can be assessed by:

a) Comparing incidence of disease

b) Comparing prevalence of disease

Using mortality rates

Using survival rates

(1)

1.5. All are disadvantages of case-control studies except:

Incidence rate cannot be ascertained

b) Bias can be introduced in selection of controls

It is unsuitable for studying rare diseases

It is reliant on respondents' memory or reliable record keeping

(1)

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1.6. Which of the following statements is not true about cross-sectional studies?

a) Based on a single examination at one point in time

b) More useful for chronic diseases

Provides very little information about the natural history of disease

d) Can help in identifying risk factors for disease

(1)

1.7. All are advantages of cohort studies except:

a) Several outcomes related to exposure can be studied simultaneously

b) Bias is minimized

It is suitable for studying rare diseases

Dose response to exposure can be studied

(1)

1.8. Which of the following statements is true about ecological studies?

a) The study units are the individuals within the population

b) More useful for chronic diseases

It makes comparison between large populations

It demonstrates trends over time

(1)

1.9 Learners' annual academic performance were compiled and ranked, as "first",

"second", "third", "fourth", and so on. This belongs to what scale of measurement?

a) nominal

b) ordinal

c) interval

d) ratio

(1)

1.10 The normal distribution curve is dependent on:

a) Mean and sample

b) Mean and median

c) Median and standard deviation

d) Mean and standard deviation

(1)

Indicate which of the following is true orfalse:

1.11 The difference between the proportion of cases interviewed and the proportion of

controls interviewed could cause selection bias.

(1)

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1.12

1.13

1.14

1.15

1.16.

1.17

1.18

1.19

1.20

Descriptive studies could be used to generate hypothesis.

(1)

Ecological studies are used to monitor trends of events over a long period of time

in the same population.

(1)

By matching the controls to the cases on age, it is ensured that age will not be a

confounder.

(1)

Restricting the study to non-smokers introduces smoking as a confounder in the

study.

(1)

A pie chart is useful in presenting qualitative data.

(1)

An advantage of the cohort design compared to a case-control study design is

that in a cohort study one can address multiple outcomes.

(1)

Participant observation can be used to collect quantitative data.

(1)

Cross-sectional studies are limited by their lack of generalisability, but are

powerful in that they directly measure risk.

(1)

Cross-sectional studies cannot directly assesscausal inference because they

measure disease and exposure in a person at the same point in time.

(1)

Question 2

Explain the following terms used in health research:

(Each correct answer earns 2 marks)

2.1 Bias

2.2 Variable

2.3 Hypothesis

2.4 Confounding

2.5 Autonomy

2.6 Volunteer effect

2.7 Type 2 error

2.8 Confidence interval

2.9 Probability sampling

2.10 Critical region

(20 marks)

Question 3

(20 marks)

3.1 Identify each of the following as either qualitative (specify nominal or ordinal) or

quantitative (specify discrete or continuous).

3.1.1. Coliform count in water sample

(2)

3.1.2. Level of satisfaction with health services

(2)

3.1.3. Weight in kg

(2)

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3.1.4. Numbers of days admitted in hospital

(2)

3.1.5. Gender

(2)

3.2 Select the most suitable sampling method for the following situations (One method for

each situation):

3.2.1 Selection of cases of individuals with sexually transmitted infections

(2)

3.2.2 Selection of participants for a survey on obesity among NUSTstudents (2)

3.2.3 Selection of health officials for interview on evaluation of community

health interventions in Windhoek.

(2)

3.3 Select the most suitable study design for the following situations:

3.3.1 A municipality wants to determine the acceptability of a do-it-yourself

water purification method among residents in an informal settlement.

They also need to determine the sources of water and occurrence of

water borne diseases among the residents.

(2)

3.3.2 The municipality wants to determine if the do-it-yourself water

purification method improved the quality of drinking water among

residents in an informal settlement. After providing the water

purification method to a random sample of residents of the area,

they collect water samples from both those who utilised the water

purification method and a random sample of those who did not utilise

the method and compare the quality of the water.

(2)

Question 4

(20 marks)

4.1 Outline the characteristics of the X2-distribution.

(4)

4.2 Highlight four (4) potential sources of error in studies and how to overcome each

error mentioned.

(8)

4.3 Discussfocus group discussions.

(8)

Question 5

(20 marks)

5.1 The weight of children under 5 years of age is distributed closely normally, with a mean

of 17 kg and standard deviation of 6 kg. A Nutritionist is trying out a certain diet for its

impact on nutritional status among children under-5. A random sample of 42 children

placed on the diet were weighed after 2 months, and an average weight of 21 kg was

obtained. Does the diet make a difference in the average weight of the under-S's?

(8)

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5.2 A group of occupational hygienists follow a g·roup of workers in a noisy factory who

consistently make use of PPEto protect their ears from noise for 18 years compared to

another group of workers who do not use of PPEto protect their ears from noise. The

occupational hygienists want to determine if there is a difference in the incidence of

hearing loss between the two groups over the 18 year period. Of 110 workers who

consistently make use of PPE,10 develop hearing loss and of 60 workers who do not use

PPEconsistently, 15 develop hearing loss.

5.2.1 State the study design used.

(1)

5.2.2 Design a table and insert the information above.

(4)

5.2.3 Analyse the results of the study and conclude on the findings.

(7)

Good luck!!!

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Z table

.00

.01

.02

.03

.04

.OS

.06

.07

.08

.09

.5000

.5040

.5080

.5120

.5160

.5199

.5239

.5279

.5319

.5359

.5398

.5438

.5478

.5517

.5557

.5596

.5636

.5675

.5714

.5753

.5793

.5832

.5871

.5910

.5948

.5987

.6026

.6064

.6103

.6141

.6179

.6217

.6255

.6293

.6331

.6368

.6406

.6443

.6480

.6517

.6554

.6591

.6628

.6664

.6700

.6736

.6772

.6808

.6844

.6879

.6915

.6950

.6985

.7019

.7054

.7088

.7123

.7157

.7190

.7224

.7257

.7291

.7324

.7357

.7389

.7422

.7454

.7486

.7517

.7549

.7580

.761 I

.7642

.7673

.7704

.7734

.7764

.7794

.7823

.7852

.7881

.7910

.7939

.7967

.7995

.8023

.8051

.8078

.8106

.8133

.8159

.8186

.821~

.8238

.8264

.8289

.8315

.8340

.8365

.8389 I

1.0

.8413

.8438

.8461

.8485

.8508

.8531

.8554

.8577

.8599

.8621 I

1.1

.8643

.8665

.8686

.8708

.8729

.8749

.8770

.8790

.8810

' .8830 I

1.2

.8849

.8869

.8888

.8907

.8925

.8944

.8962

.8980

.8997

.9015

1.3

.9032

.9049

.9066

.9082

.9099

.9115

.9131

.9147

.9162

.9177

1.4

.9192

.9207

.9222

.9236

.9251

.9265

.9279

.9292

.9306

.9319

1.5

.9332

.9345

.9357

.9370

.9382

.9394

.9406

.9418

.9429

I .9441 I

1.6

.9452

.9463

.9474

.9484

.9495

.9505

.9515

.9525

.9535

i .9545

1.7

.9554

.9564

.9573

.9582

.9591

.9599

.9608

.9616

.9625

.9633

1.8

.9641

.9649

.9656

.9664

.9671

.9678

.9686

.9693

.9699

.9706 i

;

1.9

.9713

.9719

.9726

.9732

.9738

.9744

.9750

.9756

.9761

I .9767

2.0

.9772

.9778

.9783

.9788

.9793

.9798

.9803

.9808

.9812

.9817 I

2.1

.9821

.9826

.9830

.9834

.9838

.9842

.9846

.9850

.9854

I .9857

2.2

.9861

.9864

.9868

.9871

.9875

.9878

.9881

.9884

.9887

.9890

2.3

.9893

.9896

.9898

.9901

.9904

.9906

.9909

.9911

.9913

.9916 I

2.4

.9918

.9920

.9922

.9925

.9927

.9929

.9931

.9932

.9934

.9936

2.5

.9938

.9940

.9941

.9943

.9945

.9946

.9948

.9949

.9951

.9952 I

2.6

.9953

.9955

.9956

.9957

.9959

.9960

.9961

.9962

.9963

.9964

2.7

.9965

.9966

.9967

.9968

.9969

.9970

.9971

.9972

.9973

I .9974

2.8

.9974

.9975

.9976

.9977

.9978

.9979

.9980

.9981

2.9

.9981

.9982

.9983

.9984

.9985

.9986

;

3.0

.9987

.9988

.9989

.9990

I .9990

3.1

.9990

.9991

.9992

.9993

I .9993

3.2

.9993

.9994

.9995

3.3

.9995

.9996

i .9997 !

3.4

.9997

! .9998

8 Page 8

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t Table

cum. prob

one--tail

t ..511

0.50

t.TS

0.25

t.311

t .ll!

0.20 0.15

t.Jltt

t_g5

t.111s

t.JiOs t1m t.-~

0.10 0.05 0.025 0.01 0.005 0.001 0.00051

two-tails 1.00 0.50 0.40 0.30 0.20 0.10 0.05 0.02 0.01 0.002 0.001

0.00.() \\.000

t.376

1.963 3.078 6.314

12.71 3 .82 63.66 318.31 636.62

2 0.000 0.816

1.00t

1.388 1.8813 2.920 4.31l3 l>.885 Q.li25 22..327 31.599

3 0.000 0.765 0.978 1.250

.638 2.353 3.182 4.541 5.841 0.2 5 2.924

4 0.000 0.74

0.941 1.190

.533 2. 32 2.776 3.747 4.&4

7.173 8.6 0

o:na 0.000 0.727

o:000

0.Q20 1. 15<:l t.470 2.015

Q:.906- (134, t'.+10 1.~3

2.::,71

2447

3.3-65 4.032

'3r.143 :no1

5.sn

8.800

5.851}"

tl®O

_o~-

0.000·

0.000

0:000

.. ,.too o0.:7r1o1e~

0,..889

,UHl

t:tos

t41_5

l.387

0:700

0.700

0.697

0.$3:

0.87Q

. 0.876

;;._003l..338732

l.088 L363

1.m f.995

.,.&.60

i;:2!..~3M.

2.900

2.896

'2,2tfa 2.821

1._8'11'

"2.784•-

1.7tl6 2.20i

2.718

3.4~

f.a.5.5

3..250

'3-.:16~

3:1oe·

U8!> 5.408

4.501: ' '·,\\!J.1.)4l,

-4..2Q7 4.7811

4.14;1 4.Ji87·

4.025 4.437

12 0.000 0.695 0.873 1.083 1.356 1.782 2.179 2.881 3.055 3.B30 4.3 8

13 0..000 0.694 0.870 t.079

.350

14 0.000 0.692 0.888 1.076 1.345

p:.ooo 15 0.000 0.69

0.8136 1.074

.341

ffl

0;600 0.1385 1.07t 1.~37

17 ·0.000,: 0.600 -0.863

ta 0.000 o:68.6 0.862

19 0.000 0:.688 o..~

2'() 01>00·

0.860

21 0.000 0.686 o.ssg

1:t)&f .3'33

1.0~7 1.330

.0136' 1.328

1.0M'

1~063

t.325 ..

.323

22 0.000

23 0.000

0.686

0.68~

0.858

1.06

.32

.oeo 1.3 HI

24 0.000 0.685 0.857 1.059

.318

25 0.000 0.884 0.856

.058 1.316

-0.000

0.000

0:.-684

0~84

Q.~

e.aM

·t.058 .315

1.-314

28 OA,00 o.683 0.855 .056

.;113

2Q OJlOO o.~ 0.854 j.056

-~1"1

30 . ,0.000· 0.683 0.~54 t.055 1:310·

40 0.000 0.68

0.851 1.050 1.3<03

00 0.000 0.679 0.848 1.045 1.2Q6

80 0.000 0.678 0.846 1.043 1.2Q2

1.771

1.781

t.753

1.746

1.740

t.rn

i.m

1.~5

1.721

1.717

1.714

1.711

1.708

1.700

1.7W

1.701

1.009

1.697

1.684

t.671

l.i:364

2.160 2..850 3.0'2.

2. 45 2.624 2.977

2. 31 2.602 2.947

2.11.0 ··2.583'2.821

- 10: 2.56-7 2,1198

,lL1C.1 2.562 2.578

200$ 2...539 .2..1361

,2.osa i~8

.284&

2.080 2.518 2.831

2.074 2.508 2.8 9

2.059 2.500 2.807

2.084 2:.492 2.7g7

- 2.050

:2,~·

2.485 2787

,2;_47g_ WJJ

2.052 .2.~73 i77'1

2.048 2.AW 2.763

2..045 2Ad2 2.756

2.q,t~ 2.457 2.750:

2.021 2.423 2.704

2.000 2.300 2.6130

1.990 2.374 2.639

3.852 4.221

3.787 4.140

3.733 4.073

3-.686 4.015

3..646 3..005

3$10 3.922

a.~m:1 3.~

3.552

3.527

3.850

3.8Q

:t505 3.7~2

3.485 3.768

3.467 3.745

3.450

3..~

3.42l

3.725

':j,_7{Jf

~.e.oo;

3..408 3.674

a.3s;fo 3.659",

a.ass 3.~

3.307 3.551

3.232 3.4e,O

3.195 3A 6

100

1000

0.000

0.00.Q

·0;000

0.677

0.675

0.674

50%

0.845

0.842

0.842.

60%

1.042

.037

t.038

70%

l.2QO 1.660 1.984

.282 1.648 1.002

uaz· l.64!l 1-;000

80% 90% 95%

Confidence Level

2.364

2.330

'2.326

98%

2.626

2.581

3.174

3.0'JS

3.300

2'.;576 3.000 -3-~1

ggo,{, .99.8% 99.9%

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