UNIVERSITI MALAYA
ACADEMIC SESSION 2020/2021: SEMESTER 1
SIX1003 BIOSTATISTICS: TEST 1
DECEMBER 2020 TIME: 1 HOUR 30 MINUTES
INSTRUCTION TO THE CANDIDATES: ANSWER ALL QUESTIONS.
YOU MAY WRITE YOUR ANSWER IN DIFFERENT SHEETS OF PAPER, SCAN AND SUBMIT IN PDF FORMAT.
FOR THE OBJECTIVE QUESTIONS, PLEASE WRITE DOWN YOUR ANSWER (A/B/C/D OR E) IN YOUR ANSWER SHEET
FOR THE SUBJECTIVE QUESTIONS, PLEASE WRITE THE WORKING CALCULATION CLEARLY IN YOUR ANSWER SHEET
(This question paper consists of 14 questions in 3 printed pages
Name: ___________________________________________ Registration Number: _____________________________ Group: __________________________________________
Objective question: 1 mark each
1. Which one of the following sampling methods is a probability method?
a. Quotasampling
b. Systematic sampling
c. Judgement sampling
d. Convenientsampling
e. Noneoftheabove
For question 2 and 3, refer to the following two-way table. Each number is symbolized as Xij.
2. å3æå4 ö2
ç Xij÷=
i=1
2
3
4
j=1
3
4
5
3
2
9
7
7
6
3
2
2
1
6
4
5
1
8
2
i=1 è j=3 ø
3.å3æå3 ö2 ç X2÷
=
a. 139 b. 427 c. 203 d. 145 e. 361
ij i=1 è j=2 ø
a. 188 b. 697
c. 225 d. 12534 e. 21171
4. Benefit of using mean include all the following except:
a. Takecarealltheobservations
b. Representallobservations
c. Can be used in operation of algebra
d. Isinfluencedbyextremevalue
e. Easy to calculate
5. One coin is tossed 100 times and have an event (“success”) for 43 heads. The “q” value is:
a. 0.43
b. 43
c. 0.57
d. 57
e. Noneoftheabove
6. If Z is a random standard normal variable, find 𝑃 (−1.25 ≤ 𝑍 ≤ 2.21)
a. 0.1192 b. 0.8808 c. 0.9864 d. 0.4285 e. 0.0136
7. Three books are to be selected at random without replacement out of nine books. The number of possible selections are:
a. 15
b. 84
c. 6
d. 32
e. Noneoftheabove
8. Which of the following cannot give binomial distribution?
a. Childrengender
b. Pregnancy test result
c. Tossing a coin
d. Footballgame
e. Cropyield
9. Ten percent of the bulbs produced by a factory are defective. A sample of 5 bulbs is selected randomly and tested for defect. Find the probability that two bulbs are defective
a. 0.0921 b. 0.3142 c. 0.4095 d. 0.051 e. 0.0729
10. If X~N (510, 36), then standard deviation σ is:
a. 100 b. 51 c. 36 d. 6
e. 510
3
11. A survival rate of a slope plant on an embankment is 85%. With an assumption that 4 plants are needed to strengthen an embankment, determine the probability of having the following event to be occurred:
a) Embankment has strengthened when all four plants survived.
b) Embankment has failed because only one plant survived
(2 marks)
(2 marks)
c) The stability of the embankment has been questioned because only 1 or > 1
plant died
(3 marks)
12. A box contains fertile and infertile seeds and the percentage of infertile seeds is 2%. a) Find the amount of infertile seeds expected in a box containing 10000 seeds.
b) What is the mean and variance?
(2 marks) (3 marks)
13. The distance travelled by the University Malaya employees can be modelled by a normal distribution with a mean of 7.5 km and standard deviation of 2.5. Find the probability that the distance travelled to work by a randomly selected employee is:.
a) less than 11 km.
a) between 5.5 km and 10.5 km
(2 marks) (3 marks)
14. One sample of 64 plants with a mean of leaf area of 1100 cm2 was selected from a population with a mean of leaf area of 1000 cm2 and a standard deviation of 200. Test whether the leaf area has increased after applying the new fertilizer.
a) State the hypothesis test for the above observation.
(1 mark)
b) Do a suitable test for the above data at a significance level of 95%. Draw a conclusion.
(5 marks)
c) Determine the confidence interval at level of 95% for the mean of leaf area for this sample.
(2 marks)