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Ens 501: Statistical Analysis Techniques Question Paper
Ens 501: Statistical Analysis Techniques
Course:Master Of Environmental Science
Institution: Kenyatta University question papers
Exam Year:2011
DATE:
Friday 25th November 2011
TIME:
5.30 p.m – 8.30 p.m
INSTRUCTIONS
Answer question ONE and any other FOUR
1. a)
What is statistics? Point out its importance in the field of environmental science.
[5marks]
b)
Explain the concepts of correlation and regression and compare their usefulness.
[7marks]
c)
It is proposed to conduct a sample survey to obtain information on the study
habits of the college students at Kenyatta University and the facilities for study
available to them.
Give the Performa of the questionnaire you would use for the purpose giving at
least ten relevant questions.
[10marks]
2. a)
A team of 12 experts was invited to rate two types of corporate practices in terms
of their perceived environmental impacts using a system that scale the practice
from „0? (terribly degrading) to „10? (superb in protection). The results are given
below:-
Page 1 of 4
Team No. 1 2 3 4 5 6 7 8 9 10 11 12
Practical a 9 5 2 9 6 5 7 5 5 7
8
9
Practical b 7 6 5 7 7 4 6 5 4 6
9
7
i)
Use spearman rank-order method to compute the correlation coefficient between the
two practices.
[5marks]
ii)
Interpret and discuss your findings.
[2marks
b)
Distinguish between parametric and non-parametric test and give the advantages of using
non-parametric test.
[5marks]
3. a) Define “secondary data”. State their chief sources and point out the danger involved
in their use. What precautions are necessary before using such data?
[4marks]
b) What is statistical enquiry? Describe the main stages in a statistical enquiry.[8marks]
4. a) Distinguish between the following pairs of statistical concepts.
i)
Arithmetic mean and median.
[4marks]
ii)
Variance and standard deviation.
[4marks]
b)
For each of the concepts mentioned in (a) above, explain its significance in the
interpretation of research findings.
[3marks]
c)
An environmental researcher recorded in the table below carbon dioxide concentration
emitted from the various factories.
Carbon dioxide (ppm)
No. of factories
30.00 – 32.99
2
33.00 – 35.99
4
36.00 – 38.99
26
39.00 – 41.99
47
42.00 – 44.99
15
45.00 – 47.99
6
Determine the standard deviation.
[5marks]
Page 2 of 4
5. In an experiment to study the effect of a certain pesticide upon mice, a researcher established
sixteen counting points and for each, he set traps containing pastes of varying concentrations
of the pesticides. The data collected is displayed in the table below.
Observation point
Pesticides
No. of Mice
(mg)
A
50
230
B
100
212
C
150
212
D
200
190
E
250
150
F
300
150
G
350
115
H
400
120
I
450
79
J
500
61
K
550
52
L
600
39
M
650
30
N
700
15
O
750
20
P
800
5
a) Compute the coefficient of correlation between pesticide concentration and the number of
mice and interpret and discuss your findings.
[5marks]
b) i)
Use the provided graph paper to show the relationship between pesticide
concentration and the number of mice.
[4marks]
ii)
Draw an estimated line of best fit on the graph and give the equations.
[3marks]
6. a) Describe and give properties of the Normal Distribution.
[4marks]
b) The weights in Kilogrammes of babies born in a polluted environment is given in the
table below.
2.39
2.35 2.32 2.35
2.26
2.35 2.37 2.33
2.34
2.42 2.43 2.45
2.41
2.25 2.36 2.28
2.39
2.38 2.42 2.28
Page 3 of 4
2.33
2.35 2.32 2.34
2.36
2.34 2.35 2.27
2.31
2.39 2.31 2.36
2.29
2.38 2.40 2.30
2.36
2.24 2.35 2.37
2.41
2.36 2.30 2.35
2.33
2.46 2.36 2.32
2.38
2.27 2.37 2.35
2.34
2.30 2.29 2.44
2.32
2.40 2.32 2.40
i)
Using appropriate intervals, construct a frequency distribution of the weights.
[3marks]
ii)
Determine – Geometric mean
[3marks]
- Semi-Internaqurtile Range.
[3marks]
7. a) State the two basic statistical laws upon which the sampling techniques depends.
[3marks]
b) Define the term hypothesis and explain the procedure generally followed in tesing a
hypotheses.
[4marks]
c) An environmental research wishes to test a new organic fertilizer to find if it has an effect on
maize yield.
i) State four possible hypotheses and point out the differences between one tail and two tail
test in hypothesis.
[2marks]
ii) Explain using the above example, type I and type II errors and state which one is
preferable and why.
[3marks]
Page 4 of 4
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