EPD711S - EPIDEMIOLOGY 3 - 2ND OPP - JULY 2022 :: NUST past examination papers between 2020 and 2024

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EPD711S - EPIDEMIOLOGY 3 - 2ND OPP - JULY 2022

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EPD711S - EPIDEMIOLOGY 3 - 2ND OPP - JULY 2022

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nAm I Bl A un IVE RSITY

OF SCIEnCE Ano TECHnOLOGY

FACULTYOF HEALTH,APPLIEDSCIENCESAND NATURALRESOURCES

DEPARTMENTOF HEALTHSCIENCES

QUALIFICATIONS:BACHELOROF ENVIRONMENTALHEALTHSCIENCESB, ACHELOROF SCIENCEIN

HEALTHINFORMATIONSYSTEMSMANAGEMENT, BACHELOROF HUMAN NUTRITION

QUALIFICATIONCODE:08BOHS,07BHIS,

08BOHN

LEVEL: 7

COURSECODE: EPD711S

COURSENAME: EPIDEMIOLOGY3

SESSION:

JULY2022

PAPER:

THEORY

DURATION: 3 HOURS

MARKS:

100

SUPPLEMENTARY/SECONDOPPORTUNITYEXAMINATION 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.

{20 marks)

1.1 In a randomised controlled trial, which of the following best describes the primary

reason to randomise patients to treatments?

a) To create two treatment groups that are similar at baseline on both known and

unknown factors associated with the expected outcome

b) Prevent bias introduced when the patients know what type of treatment they

are receiving

c) Prevent bias introduced when the investigators know what type of treatment .

the patients are receiving

d) None of the above

(1)

1.2 A researcher restricts selection of cases and controls to those with at least 70

percent of their lifetime years with a known source of drinking water. This

approach was used to reduce which type of bias?

a) Confounding bias

b) Selection bias

c) Information bias

d) Random error

(1)

1.3 Cluster sampling can be used when:

a) The sampling frame is known

b) Selecting participants for Focus group discussions

c) Selecting participants who are hidden in the population

d) A large population has homogenous units

(1)

1.4 Consent by proxy:

a) Exempts the researcher from getting individual consent

b) Means that the researcher gets consent from an institutional research

review committee

c) Applies to research involving people with diminished autonomy

d) Involves research with pregnant women

(1)

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1.5 Self-governance is the driving force behind which ethical principle?

a) Autonomy

b) Beneficence

c) Justice

d) Respect for persons

(1)

1.6 Communal consent:

a) Exempts the researcher from getting individual consent

b) Means that the researcher gets consent from an institutional research

review committee

c) Applies to research involving people with diminished autonomy

d) Means that the researcher gets consent from a community/institutional

gatekeeper

(1)

1.7 John Snow made numerous contributions in health including all the following,

except:

a) Developing the spot map

b) Administration of anaesthesia during labour for the first time

c) Developing the cholera vaccine

d) Controlling the cholera outbreak in London

(1)

1.8 The following are characteristics of the Chi-square distribution, except:

a) Symmetrical about the mean

b) Completely specified by the degree of freedom

c) Does not have negative values

d) Used for qualitative data

(1)

1.9 The following is true about longitudinal studies except:

a) They are likened to a film as cross-sectional studies are liked to a snap-shot

b) They are useful in studying trends of events

c) They are useful in studying rare outcomes

d) They involve repeated observation over a prolonged period

(1)

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1.10 Controls were selected as a random sample using the population register of a certain

County Council. Which of the following best describes the primary purpose of using a

random sample in this study?

a) Maximize generalizability by obtaining a statistically representative sample.

b) Select a control group that was as similar as possible to those in the population.

c) Provide an estimate of the exposure in the population from which the cases arose.

d) Select a control group with habits similar to those in the population of cases. (1)

Indicate the scales of measurement for each of the following variables:

1.11 Ethnicity

(2)

1.12 Number of days of illness

(2)

1.13 Height in centimetres

(2)

1.14 Students' year of study

(2)

1.15 Marital status

(2)

Question 2

Explain the following terms used in health research:

{Each correct answer earns 2 marks)

2.1 Critical limit

2.2 Level of significance

2.3 Null hypothesis

2.4 Sampling error

2.5 Statistical power

2.6 Confounding

2.7 Type 1 error

2.8 Berksonian bias

2.9 Non-probability sampling

2.10 Sampling frame

(20 marks)

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Question 3

(20 marks)

Identify the suitable study design in the scenarios provided below, highlighting characteristics

identified:

3.1 A study was carried out to establish a relationship between exposure to

radiation and breast cancer. The study group comprised of 104 persons who had

been exposed to radiation while 158 persons who were not exposed to radiation

were used for comparison. The study subjects were followed up over 25 years

after which data was collected on their development of breast cancer.

(4)

3.2 A researcher wants to quantify the magnitude of Schistosomiasis in a village

located close to a river having freshwater snails. Urine samples were collected

from 30% of the community members to examine for Schistosoma and

community members were asked the presence of urinary symptoms and their

source of water for domestic purposes.

(4)

3.3 Researchers conducted a study to assessa possible association between eating

fish and heart disease. Study subjects with heart disease were recruited into one

group and people without heart disease were recruited into another group for

comparison. Both groups were asked about their consumption of fish.

(4)

3.4 After consuming a meal with his family, a five year old boy begins to have severe

abdominal pains. He is not known to have any food allergies. Samples of the meal

consumed were analysed and it was found to contain a certain heavy metal. A

detailed report regarding the event and all laboratory tests was compiled.

(4)

3.5 In order to plan for Flu vaccines in Namibia, the Ministry undertake a study in

which they demonstrate trends in the prevalence of Flu over the last 5 years. (4)

Question 4

4.1 Outline the characteristics of the z-distribution.

4.2 Explain why it is important to pre-test study instruments.

4.3 Discuss any two (2) non-probability sampling methods.

4.4 Discussthe characteristics of any data collection method.

(20 marks)

(5)

(4)

(6)

(5)

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Question 5

(20 marks)

5.1 Calculate the sample size for a study on effectiveness of environmental

measures to control schistosomiasis in a community with 800 households,

where the prevalence of malaria is 28%, if the study is conducted at 95%

confidence interval.

(5)

5.2 What would be the most appropriate sampling method to be used in selecting

the sample from the above community if the population is homogenous, all the

houses are numbered and a list of all the household heads is available? Describe

how this sampling method will be applied.

(5)

5.3 It is claimed that in a particular population, the mean amount of money a person

has on him is cash is $50, with a standard deviation of $8. To test this claim, a

researcher is taking a sample of 26 persons from the population, and he finds

that they have a mean of $52. Is the amount of cash people have on them more

than $50?

(10)

Good luck!!!

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1.0

I.I

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

3.t

3.2

3.3

3.4

·-·-·······--

.00

.5000

.5398

.5793

.6179

.6554

.6915

.7257

.7580

.7881

.8159

.8413

.8643

.8849

.9032

.9192

.9332

.9452

.9554

.9641

.9713

.9772

.9821

.9861

.9893

.9918

.9938

.9953

.9965

.9974

.9981

.9987

.9990

.9993

.9995

.9997

.01

.5040

.5438

.5832

.6217

.6591

.6950

.7291

.7611

.7910

.8186

.8438

.8665

.8869

.9049

.9207

.9345

.9463

.9564

.9649

.9719

.9778

.9826

.9864

.9896

.9920

.9940

.9955

.9966

.9975

.9982

.9987

.9991

.9993

.9995

.9997

.02

.5080

.5478

.5871

.6255

.6628

.6985

.7324

.7642

.79.19

.8212

.8461

.8686

.8888

.9066

.9222

.9357

.9474

.9573

.9656

.9726

.9783

.9830

.9868

.9898

.9922

.9941

.9956

.9967

.9976

.9982

.9987

.9991

.9994

.9995

.9997

.03

.5120

.5517

.5910

.6293

.6664

.7019

.7357

.7673

.7967

.8238

.8485

.8708

.8907

.9082

.9236

.9370

.9484

.9582

.9664

.9732

.9788

.9834

.9871

.9901

.9925

.9943

.9957

.9968

.9977

.9983

.9988

.9991

.9994

.9996

.9997

.04

.5160

.5557

.5948

.6331

.6700

.7054

.7389

.7704

.7995

.8264

.8508

.8729

.8925

.9099

.9251

.9382

.9495

.9591

.9671

.9738

.9793

.9838

.9875

.9904

.9927

.9945

.9959

.9969

.9977

.9984

.9988

.9992

.9994

.9996

.9997

Z table

.OS

.06

.5199

.5239

.5596

.5636

.5987

.6026

.6368

.6406

.6736

.6772

.7088

.7123

.7422

.7454

.7734

.7764

.8023

.8051

.8289

.8315

.8531

.8554

.8749

.8770

.8944

.8962

.9115

.9131

.9265

.9279

.9394

.9406

.9505

.9515

.9599

.9608

.9678

.9686

.9744

.9750

.9798

.9803

.9842

.9846

.9878

.9881

.9906

.9909

.9929

.9931

.9946

.9948

.9960

.9961

.9970

.9971

.9978

.9979

.9984

.9985

.9989

.9992

.9994

.9996

.9997

.07

.5279

.5675

.6064

.6443

.6808

.7157

.7486

.7794

.8078

.8340

.8577

.8790

.8980

.9147

.9292

.9418

.9525

.9616

.9693

.9756

.9808

.9850

.9884

.991 I

.9932

.9949

.9962

.9972

.9979

.9985

.9989

.9992

.9995

.9996

.9997

.08

.5319

.5714

.6103

.6480

.6844

.7190

.7517

.7823

.8106

.8365

.8599

.8810

.8997

.9162

.9306

.9429

.9535

.9625

.9699

.9761

.9812

.9854

.9887

.9913

.9934

.9951

.9963

.9973

.9980

.9986

.9990

.9993

.9995

.9996

.9997

.09

.5359

.5753

I .6141

.6517

.6879

.7224 :

i .7549 '

I .7852

I .8133

.8389

.8621 !

I .8830

! .9015

.9177

I .9319

.9441 I

' .9545 i

.9633 j

.9706

' .9767

I .9817

i .9857

I .9890

.9916

.9936

.9952

.9964

.9974

.9981

.9986

.9990

.9993

.9995

.9997

.9998

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t Table

cum.prob

one-tail

t ..Ill

0.50

f .75

0.25

t,.00

t .&!

0.20 0.15

t.lk,

0.10

f_g5

0.05

t..91s

0.025

t_.., t..l)~S

0.01 0.005

t __

f !>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

1 0.000

2 0.000

3 0.000

4 0.000

.000

0.816

0.76-5

0.74

t.37o

· .061

0.978

0.94

1.963

'-388

.250

. 00

3.078

l.8'36

.638

1.533

6.314

2.920

2.353'

2.!32

12.71

4.303

3.1-82

2.776

31.82

IH165

4.5-41

3.747

63.66

9.925

5.841

4.e04

318.31

22.327

10.2 5

7.173

63o.62

31.599

2.924

8.6 0

-o:ooe· 5

0.000 0.727 0.820

0.000 o.,j:a

1.156

'1,134

.470 2.015 2.571

·1.410"1lt,:i3: 2.447

3.365

3.'143

4.032. 5.&l3 6.800

3'.707 6.208 5..Q58

·7

0.000

0..000

0.71 ·,p..8fi.6 t t,.19 .415

b.700 , O.SSQ 1.100 1.3'tl7

l,.S9p

1.800

Z3,55- ;:°lOOB

2.~

2.~--

3.35c5

..(785 . 5.lf08

4.501 .5.041

9 O.OO(f Q.703 ·o.883' .too .-383 .833 2,:w_2 '2.821 3..250, ,ug7 4.781

·o.ooo 10 ·D.000 O,JQQ ~-a-zs -9~

0.697 0.-876 l.088

1.37:? 'i\\8-1:? 2.22.8 . "2.71X• -S.teB .144

1.363 1.796 i201

2.718 3.106 4.025

4._J_i,87/. ·

4.437

12 0.000 01l95 0.873

.083 1.356 1.782 2. 79 2.e.a1 3.L\\55 3.930 4.318

13 0.000 0.694 0.870 l.07Q

.350

14 0.000 0.692 0.888 1.076 1.345

15 0.000 0.61:,

1.7

0. .0-0.0...

0,000

0.6. 00

.. 0.689

18 o.oq<f. 0.-688

0.868 1.074

.34

:009 0~

't,071 1.337

Q..863'.

;•_333

0'.8&2 1-®7 .t.330

lg 0..000 Q.688 '.0,86

.066' 1:32S

20 OllOO 0.6S7 0.861? ·.o64· l.325

2, 0.000 0.600 0.859

.063 1.323

22 0.000 0.686 0.858

.061 1.32

23 0.000 0.68.5 0.858 t.060 1.319

24 0.000 0.1385 0.857 1.059 1.318

25 0.000 0.684 0.856

.058

.316

26 0.000- 0-:.fflK ·o.S56 1.058 .31'5

'ti 0.000 0.684 0.856

OS( 1,314

28 .O.DOO 0..683 _tl.855 l.056 1.31;3

2Q 0..000· 0.683 o.~

hO!;io. .$tt

:ro O.OQO· 0.683 ·-0:~

Ul55

.310

40 0.000 0.881 0.85t

1.050

t.3-03

1.771 2. 60 2.650 3.012

1.761 2.f45 2.624 2.977

1.753 2.131 2.602 2.947

J.746 2.'f20 -2.&83' 2.921

1,740 ':2:-HO ·2.5a7 1898

1.734 ,,LOl 2.562 2..878

tns 2003 ·2-539 2..861

1+72~ ·2.096 2.521>, 2.845

1.721 2.080 2.5i8 2.831

1.717 2.074 2.508 2.BIB

1.714 2..069 2.500 2.807

f.711 2.004 2.492 2,7g7

1.708 2.050 2.485 2.787

1.706 ·~056 2.47-Q 2.27~

1,703 2-..()52. 2.-03 2.771

1.701 ':2.0'-f8 2.467 2.763

1.009 2.045- ,.2:...ffl2 2.756

1..697 Z.042 2:~

2...151)

1.684 2.021 2.423 2.704

3.852

3.787

3.733

iea6

3.846

3,.{UO

3.678

3.552

3.527

3..505

3..485

3.467

3.450

3.435

3.42

l..408

3-.396

3,,385

3.307

4.221

4.140

4.073

4.1)15

3.965

-.3,822

3.883

3.8&1

3.8 Q

3.7£12

3.768

3.745

3.725

''a:1rrf'

3.!¼l(l

3·.674

3:..6001

3.646

3.5-51

60 0.000

80 0.000

0.879

0.678

0.848

0.846

1.045

.043

.29~

1.292

1.671

1.004

2.000

1.990

2.390

2.374

2.000

2.639

3.232

3.195

3.400

3.4 6

100 0.000

000 0.000

z '0-.000

0.677

0.675

0..674

0.845

0.842

0,842

.042

1.037

1,036

1.290

1.282

1.660

1.646

.645

1.984

1.002

1,000

2.3-64 2..626

2.330 2.581

2..326 2571} 1

3.174

3..0'J8

3_000

3.300

3.291

0% 50% 60% 70% 80% 90% 95% 98% 99% 99.8% 99.9%

Confidence Level

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Chi-square Distribution

I I df\\area .995

11 lo.00004

I .990

lo.00016

I .975

lo.00098

I .950

lo.00393

I I .900

.750

10.01579 lo.10153

I .500

lo.45494

I I I I I I .250

.100

.050

.025

.010

.005

11.32330 12,70554 13.84146 15.02339 16.63490 17.87944

I 2 lo.01003 10.02010 lo.05064 lo.10259 jo.21012 lo.57536 11.38629 12.77259 14.60517 15.99146 17.37776 19.21034 110.59663

I 3 !I 0.01112 lo.11483 lo.21580 lo.35185 !o.58437 11.21253 12.36597 14.10834 16.25139 17.81473 19.34840 111.34487112.83816

1410.20699

lo.29111 lo.48442 10.71072 11.06362 11.92256 13.35669 15.38527 17.77944 19.48773 111.14329113.27670 114.86026

10,41174 lo.55430 lo.83121 11.14548 11.61031 12.67460 14.35146 16.62568 19.23636 111.01050112.83250115.08621 !16.74960

10.67573 lo.87209 11.23734 11.63538 12.20413 13.45460 15.34812 17.84080 110.64464 112.59159 114.44938 116.81189 118.54758

II 8

lo.98926 11.23904 11.68987 12.16735 12.83311 14.25485 16.34581 19.03715 112.01704 114.06714 116.01276 118.47531 120.27774

jl.34441

il.73493

11.64650 12.17973 12.73264 13.48954 15.07064 17.34412 110.21885113.36157 115.50731117.53455120.09024121.95495

12.08790 12.70039 13.32511 14.16816 15.89883 18.34283 111.38875 114.68366116.91898l19.02277121.66599123.58935

12.15586 12.55821 13.24697 13.94030 J4.86518 16.73720 19.34182 112.54886115.98718118.30704120.48318123.20925125.18818

~12.60322

13.05348 13.81575 14.57481 15.57778 17.58414 110.34100113.70069 117.27501119.67514121.92005 124.72497 126.75685

~13.07382

13.57057 14.40379 15.22603 16,30380 18.43842 111.34032 114.84540 118.54935 121.02507 123.33666 l26.21697 128.29952

13.56503 14.10692 15.00875 15.89186 17.04150 19.29907 112.33976j15.98391119.81193 122.36203 J24.73560121.68825 129.81947

14.07467 14,66043 15.62873 16.57063 17,78953 110.16531 113.33927 ,17.11693 121.06414 123.68479 126.11895 129.14124 131.31935

II 15

I 16

!4.60092 15.22935 16.26214 17.26094 !8.s4676 111.03654 J14.33886 118.24509 122.30713 124.99579 127.48839 130.57791 132.80132

/5_14221 15.81221 16.90766 17.96165 19.31224 111.91222 115.33850 J19.36886123.54183 126.29623 l28.84535131.99993 134.26719

~15.69722

16.40776 17.56419 18.67176 110.08519 112.79193 116.33818 120.48868124.76904127.58711130.19101133.40866135.71847

~16,26480

17.01491 18.23075 19,39046 110.86494 113.67529117.33790 121.60489125.98942 128.86930 131.52638 134.80531 137.15645

~16.84397

17.63273 18.90652 110.11101 111.65091 114.56200118.33765 122.71781127.20357 130.14353 132.85233136.19087 138.58226

I 20

II 21

II 23

17.43384 18.26040 19.59078 110.85081 )12.44261 115.45177119.33743 123.82769128.41198131.41043 134.16961137.56623 139.99685

18.03365 18.89720 110.28290 111.59131113.23960116.34438120.33723 124.93478129.61509132.67057135.47888138.93217 ,41.40106

18.64272 19.54249 110.98232 112.33801 114.04149 117.23962 l21.33704l26.03927130.81328133.92444136.78071140.28936 142.79565

I!9.26042 110.19572 111.68855 113.09051 114.84796118.13730122.33688127.14134132.00690135.17246138.07563

141.63840144.18128

~,9.88623

110.85636 112.40115 113.84843 l15.65868 119.03725 123.33673 128.24115 133.19624 136.41503 139.36408 142.97982 145.55851

I 25 ,10.51965 111.52398 113.11972 114.61141 116.47341 119.93934124.33659129.33885134.38159137.65248 140.64647 144.31410 146.92789

~111.16024112.19815

113.84390 115.37916111.29188 J20.84343 125.33646130.43457135.56317 138.88514141.92317 J45.64168148.28988

I 27

I 28

/11.80759112.87850114.57338116.15140,18.11390121.74940126.33634131.52841136.74122140.11327143.19451146.96294149.64492

/12.45134 113.56471 115.30786 116.92788 118.93924 122.65716 127.33623 132.62049137.91592 J41.33714 144.46079 148.27824 j5o.99338

~113.12115

114.25645 116.04707 117.70837 119.76774123.56659128.33613 133.71091139.08747142.55697 145.72229 149.58788 ,52.33562

~113.78672

114.95346 116.79077 118.49266 !20.s9923 124.47761129.33603 134.79974140.25502 143.77297146.9792415o.89218 153.67196