[ASF]Workbook of Chapter II

Workbook Chapter 2: Applied Statistics for Business and Economics

MBA at NUM (Cambodia), Room: 15F, Group 12, 5:30 PM – 8:30 PM

Reference: Miss. Eng Channy

1/

a/ Many classes should the frequency table have

C = h(100)/h(2) = 6.64 or 7

b/ CI = (315-56)/7 = 37

c/ The bounds and mid point of each class

56 – 93 74.5

93 – 130 111.5

130 – 167 148.5

167 – 204 185.5

204 – 241 222.5

241 – 278 259.5

278 – 215 296.5

2/

a/ Classes will put in frequency table

C = h(500)/h(2) = 8.96 or 9

b/ The class interval

CI = (27500 – 19900)/9 = 844

c/ The bounds and midpoint of each class

19900 – 20744

20744 – 21588

21588 – 22432

22432 – 23276

23276 – 24120

24120 – 24964

24964 – 25808

25808 – 26652

26652 – 27496

3/

a/ Construct a frequent table for the data

Classes Frequency Cumulative Frequency

31 – 41 9 51

42 – 52 4 47

53 – 63 11 36

64 – 74 17 19

75 – 85 7 12

86 – 96 2/60 10

Relative

31 – 41 = 9x/60 = 0.15

42 – 52 = 4x/60 = 0.06

53 – 63 = 11/60 = 0.18

64 – 74 = 17/60 = 0.28

75 – 85 = 7/60 = 0.11

86 – 96 = 2/60 = 0.03

b/

More Frequency Cumulative Frequency

31 or more 9 60

42 or more 4 51

53 or more 11 47

64 or more 17 36

75 or more 7 19

86 or more 2 12

6/

Construct a stem and leaf

3 276

4 26778

5 455

6 9782

7/

Develop and interpret a histogram

8/

Construct a pie chart

9/

Construct a bar chart

10/

The boundaries of the classes be

CI = (1200000 – 1000)/10 = 119000

10000 – 129000

129000 – 248000

248000 – 367000

367000 – 486000

486000 – 605000

605000 – 724000

724000 – 843000

843000 – 962000

962000 – 1081000

1081000 – 1200000

Quiz 10 Minutes

A. Give sample xi: 15, 7, 9, 10, 15, 30

1. Median

2. Mode

B. Frequency Table

Class Frequency Calculate Mean
10 to 19 5
20 to 29 10
30 to 39 7
40 to 49 8
50 to 59 10

Answer:

A. 1- Median point = (n+1) /2, and n = 6  → Median point = (6+1)/2 = 3.5

so Median is in range of 10 and 15

Median = (10+15)/2 = 12.5

A. 2- Mode = Max(f(xi))

xi = 7, 9, 10, 15, 15, 30

→ Mode = 15

B. Calculate Mean

Class Frequency xi(Mid Point)
10 to 19 5 14.5
20 to 29 10 24.5
30 to 39 7 34.5
40 to 49 8 44.5
50 to 59 10 54.5

→ Mean = ∑(xi).fi / ∑(fi), if ∑(fi) = 40, and ∑(xi).fi= 14.5×5+24.5×10+34.5×7+44.5×8+54.5×10 = 1460

Mean = 1460/40 = 36.5

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~ by Rithy Pheath on 10/20/2009.

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