The table given below shows sales figure of iPods recorded during a Christmas festive period.
Sales
56
50
94
73
82
21
102
123
71
111
145
158
40
93
61
94
68
79
73
49
90
70
47
30
61
84
116
64
99
129
150
86
100
54
35
146
84
95
86
107
In order to make five groups of equal width, first of all range of the data is determined. From the above data, minimum and maximum figures are as follows.
Minimum = 21
Maximum = 158
Range = 158-21 = 137
Number of Classes = 5
Size of Each Class = Range / Number of Classes (Alexeyev, 2000, 44)
Size of Each Class = 137 / 5
Size of Each Class = 27.4 28
Based on the class size of 28, following class intervals are created.
Class Interval
20 - 47
48 - 75
76 - 103
104 - 131
132-159
Arranging the data into a less than cumulative frequency distribution using five groups of equal width provides following results.
Class Interval
Cumulative Frequency
Less than 19.5
0
Less than 47.5
5
Less than 75.5
17
Less than 103.5
31
Less than 131.5
36
Less than 159.5
40
1.2: Draw Graphs
1.2.1 Histogram
1.2.2 Frequency Polygon
1.2.3 “Less Than” Ogive
1.3: Ogive
1.3.1 The 65th Percentile
65th Percentile = 94
1.3.2 The Quartile Deviation
Quartile 1 = 61.00
Quartile 2 = 84.00
Quartile 3 = 101.50
Quartile 4= 158.00
Question 2
2.1: Mean and Standard Deviation for the Daily Trading Volumes
The daily trading volume for stocks traded on the New York Stock Exchange for 12 days in a certain period are listed below.
917 millions of shares
983 millions of shares
1046 millions of shares
944 millions of shares
723 millions of shares
783 millions of shares
813 millions of shares
1057 millions of shares
766 millions of shares
836 millions of shares
992 millions of shares
973 millions of shares
In order to calculate the mean of the daily trading volumes to use as estimate of population mean, following formula will be used:
Mean for the daily Trading Volumes =
Sum of all observations (total of daily trading volumes included in sample)
Number of observations of daily trading volumes
Mean for the daily Trading Volumes =
Mean for the daily Trading Volumes = 902.75 million of shares
In order to calculate the standard deviation of the daily trading volumes to use as estimate of population deviation, following formula will be used:
Standard Deviation = (Balnaves, 2007, 38)
Standard Deviation = =
Standard Deviation = = 114.18
2.2: Probability for a Particular Day to Have Trading Volumes less than 800 Million Shares
Probability that on a particular day trading volumes will be less than 800 million shares is calculated below:
Data:
Mean = 902.75
Standard Deviation = 114.18
X = 800
P (X < 800) = ?
As we know that,
Z = (X - Mean) / Standard Deviation (Ott, 2008, 84)
Z = (800 - 902.75) / 114.18
Z = -0.8999
P (X < 800) = P (Z < -0.8999)
P (Z < -0.8999) = 0.1840
Probability that on a particular day trading volumes will be less than 800 million shares is 0.1840.
2.3: Probability for a Particular Day to Have Trading Volumes will exceed 1 Billion Shares
Probability that on a particular day trading volumes will exceed 1 billion shares is calculated below:
Data:
Mean = 902.75
Standard Deviation = 114.18
X = 1 billion = 1000 million
P (X > 1000) = ?
As we know that,
Z = (X - Mean) / Standard Deviation (Balnaves, ...