STA1510 EXAM PORTFOLIO 2024

STA1510

BASIC STATISTICS

NOTES, QUESTIONS AND ANSWERS

FOR FURTHER CLARIFICATION PLEASE
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STA1510/201/0/2022




Tutorial Letter 201/0/2022

Basic Statistics
STA1510

Year module


Department of Statistics


SOLUTIONS TO ASSIGNMENT 01

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STA1510/201/0/2022



QUESTION 6
Only 3 shoppers (30 x 10%) of the sampled shoppers prefer to do their grocery shopping at Spar.
Option (5)


QUESTION 7

(A) Incorrect
∑끫뢶
끫뢬끫뢖끫뢬 34 + 28 + 37 + ⋯ + 40 378
�
끫뢖
=
=1
= = = 37.8.
끫뢶 10 10
(B) Incorrect
The median is a middle number in an ordered array
35+37
Median = = 36.
2
(C) Correct
∑( 끫뢖�
−)2 끫뢖(34 − 37.8)2 + (28 − 37.8)2 + ⋯ + (40 − 37.8)2
끫뢌
2
= = = 71.9556.
끫뢶 − 1 10 − 1
So,

끫뢌 =2√=끫뢌
√71.9556 = 8.4827 .
(D) Incorrect
Mode is the number that appears more than other numbers:
Mode = 40
(E) Incorrect
끫뢌 8.48
끫롬끫롬 =
× 100% = × 100% = 22.44%
�
끫뢖 37.8

Option (3)


QUESTION 8

1. Correct
끫뢌 58.14
끫롬끫롬
�
�=�
100% = × 100% = 32.90% .
끫뢖 176.7

2. Incorrect
(155+170)
Median is = 162.50.
2

3. Incorrect
끫뢶
�= ∑끫뢬끫뢖
끫뢖 끫뢬 125+140+170+⋯+310
=1
= = 176.7.
끫뢶 10

4. Incorrect
Range = 310 – 125 = 185.

3

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STA1510/201/0/2022


5. Incorrect
∑끫뢶(끫뢖
−�
끫뢖
) (125−176.7)2 +(140−176.7)2 +⋯+(310−176.7)2
끫뢌�=끫뢬 =1끫뢬 = �� � = 58.1379.
끫뢶− 1 9



Option (1)


QUESTION 9


끫뢌
� �=
끫롬끫롬 × 100%
�
끫뢖
2.6641
= × 100%
24.6923

= 10.7892%
Option (5)


QUESTION 10

Ordered data:
3 4 6 7 9 10 14 23
1. Correct
7+9
Median = 2 = 8.

2. Correct
끫뢶 + 1
끫뢈
1 = ranked data
4
8+1
= ranked data
4

= 2.25 ranked data

= 2 nd (rounded off to the nearest)

∴ 끫뢈
1 = 4.




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