Week 5 Practical : Interviews and Surveys

B User Requirement Gathering Methods

Part III – Survey Analysis (Steps and Answers below)

1. a) 2,2,2,2

Median…
Arrange the numbers in ascending order = 2,2,2,2
Middle Numbers = 2 and 2
Therefore, median = (2+2)/2 = 2

Mean = Sum of all the numbers in the dataset/count = (2+2+2+2)/4 = 2

Standard deviation of the mean…
Mean = 2
Deviation of each number from the mean,
2-2 = 0
2-2 = 0
2-2 = 0
2-2 = 0
Square of every deviations,
0x0 = 0
0x0 = 0
0x0 = 0
0x0 = 0
Mean of squared deviations,
(0+0+0+0)/4 = 0
Square root of the quotient,
√0 = 0
Therefore, standard deviation = 0

b) 0.67, 1.03, -0.38, -0.75, 0.79, -0.13, 1.57, -1.78, -0.58, -1.43

Median…

Arrange the numbers in ascending order = -1.78, -1.43, -0.75, -0.58, -0.38, -0.13, 0.67, 0.79, 1.03, 1.57
Middle Numbers = -0.38 and -0.13
Therefore, median = (-0.38)+(-0.13)/2 = -0.255

Mean = Sum of all the numbers in the dataset/count = [(-1.78)+(-1.43)+(-0.75)+(-0.58)+(-0.38)+(-0.13)+(0.67)+(0.79)+(1.03)+(1.57)]/10 = -0.099

Standard deviation of the mean…
Mean = -0.099
Deviation of each number from the mean,
(-1.78)-(-0.099) = -1.681
(-1.43)-(-0.099) = -1.331
(-0.75)-(-0.099) = -0.651
(-0.58)-(-0.099) = -0.481
(-0.38)-(-0.099) = -0.281
(-0.13)-(-0.099) = -0.031
(0.67)-(-0.099) = 0.769
(0.79)-(-0.099) = 0.889
(1.03)-(-0.099) = 1.129
(1.57)-(-0.099) = 1.669
Square of every deviations,
-1.681x-1.681 = 2.826(rounded off)
-1.331x-1.331 = 1.772(rounded off)
-0.651x-0.651 = 0.424(rounded off)
-0.481x-0.481 = 0.231(rounded off)
-0.281x-0.281 = 0.079(rounded off)
-0.031x-0.031 = 0.001(rounded off)
0.769×0.769 = 0.591(rounded off)
0.889×0.889 = 0.790(rounded off)
1.129×1.129 = 1.275(rounded off)
1.669×1.669 = 2.786(rounded off)
Mean of squared deviations,
(2.826+1.772+0.424+0.231+0.079+0.001+0.591+0.790+1.275+2.786)/10 = 1.078(rounded off)
Square root of the quotient,
√1.078 = 1.038(rounded off)
Therefore, standard deviation = 1.038(rounded off)

c) 4.7, 11, 0.42, 0.18, 6.2, 0.74, 38, 0.016, 0.26, 0.037

Median…
Arrange the numbers in ascending order = 0.016, 0.037, 0.18, 0.26, 0.42, 0.74, 4.7, 6.2, 11, 38
Middle Numbers = 0.42 and 0.74
Therefore, median = (0.42+0.74)/2 = 0.58

Mean = Sum of all the numbers in the dataset/count =(0.016+0.037+0.18+0.26+0.42+0.74+4.7+6.2+11+38)/10 = 6.155(rounded off)

Standard deviation of the mean…
Mean = 6.155(rounded off)
Deviation of each number from the mean,
0.016-6.155 = -6.139(rounded off)
0.037-6.155 = -6.118(rounded off)
0.18-6.155 = -5.975(rounded off)
0.26-6.155 = -5.895(rounded off)
0.42-6.155 = -5.735(rounded off)
0.74-6.155 = -5.415(rounded off)
4.7-6.155 = -1.455(rounded off)
6.2-6.155 = 0.045(rounded off)
11-6.155 = 4.845(rounded off)
38-6.155 = 31.845(rounded off)
Square of every deviations,
-6.139x-6.139 = 37.687(rounded off)
-6.118x-6.118 = 37.430(rounded off)
-5.975x-5.975 = 35.701(rounded off)
-5.895x-5.895 = 34.751(rounded off)
-5.735x-5.735 = 32.890(rounded off)
-5.415x-5.415 = 29.322(rounded off)
-1.455x-1.455 = 2.117(rounded off)
0.045×0.045 = 0.002(rounded off)
4.845×4.845 = 23.474(rounded off)
31.845×31.845 = 1014.104(rounded off)
Mean of squared deviations,
(37.687+37.430+35.701+34.751+32.890+29.322+2.117+0.002+23.474+1014.104)/10 = 124.748(rounded off)
Square root of the quotient,
√124.748 = 11.169(rounded off)
Therefore, standard deviation = 11.169(rounded off)

Part I – Conducting an Interview (Jackson’s Blog)
Part II – Preparing a Survey (Thomas’s Blog)