4.1 Statistical investigation (quantitative findings)
4.1.3 Quality of communication
Quality of communication construct consists of 5 questions/variables shown in Table 9.
The data of the construct is normally distributed based on the histogram shape Figure 16 and based on the skewness and kurtosis Table 13. The internal consistency/reliability of the construct is good based on Table 15.
Descriptives regarding the construct are shown in Table 41 below.
TABLE 41DESCRIPTIVES OF QUALITY OF COMMUNICATION CONSTRUCT
Descriptive Statistics
N Range Minimum Maximum Mean Std. Deviation Variance Quality of Communication 142 2.75 2.20 4.95 3.857 .52348 .274 Valid N (listwise) 142
Due to the normality assumption of t-tests, it is necessary to investigate normality of the data in different phases. The information regarding the normality of the construct in different phases is shown in Table 12. The skewness of the conceptualization phase is high. Since the sample size is small, the great skewness can negatively impact the precision of the results of t-test. Thus, this phase is considered not normal. The results of Mann-Whitney U test would be preferred if the results of the 2 tests did not match.
The skewness and kurtosis of the execution phase is high. Although it is within the acceptable range, but it can have detrimental effect on the precision of results of t-test because the sample size is not big. The sample size is 56. It is only a little bigger than 50 (50 is the ‘small sample size’ mentioned by Hair et al. (1998)). Therefore, the
execution phase is considered not normal. The results of Mann-Whitney U test would be preferred if the results of the 2 tests did not match.
Figure 17, Figure 18, and Figure 19 illustrate distribution of the 3 phases regarding quality of communication construct.
Ranks
Mann-Whitney U 1327.500
Z -1.103
Sig. (2-tailed) .270
a. Grouping Variable: Project phase
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FIGURE 16DISTRIBUTION HISTOGRAM OF QUALITY OF COMMUNICATION CONSTRUCT REGARDLESS OF PHASES
FIGURE 17DISTRIBUTION HISTOGRAM OF QUALITY OF COMMUNICATION CONSTRUCT IN CONCEPTUALIZATION PHASE
FIGURE 18DISTRIBUTION HISTOGRAM OF QUALITY OF COMMUNICATION CONSTRUCT IN PLANNING PHASE
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Descriptives of quality of communication construct in different phases are available in Table 42 including sample size, mean, standard deviation, and standard error mean.
TABLE 42DESCRIPTIVES OF QUALITY OF COMMUNICATION CONSTRUCT IN DIFFERENT PHASES
The results of independent-samples t-test and Mann-Whitney U test are presented in 3 categories as follows.
4.1.3.1 Conceptualization and planning
Descriptives of the 2 phases are shown in Table 42 including sample size, mean, standard deviation, and standard error mean.
Table 43 presents the results of independent-samples t-test (the parametric test) which also comprises the results of Levene's Test for Equality of Variances. According to the table, the variances of the phases is approximately equal and there is no significant difference in quality of communication between conceptualization and planning phases of the projects because the significance level is greater than 0.05.
Since the conceptualization phase might be too different from a normal distribution, a Mann-Whitney U test is considered to be essential for accuracy of the results. The results of Mann-Whitney U test (the nonparametric test) together with its descriptives are presented in table 44 and table 45. Based on Table 45, there is no significant
difference in quality of communication between conceptualization and planning phases of the projects because the significance level is greater than 0.05.
Group Statistics
Project phase N Mean Std. Deviation
Std. Error Mean Quality of Communication Conceptualization 29 3.7272 .60428 .11221
Planning 54 3.7991 .49193 .06694
Execution 56 3.976 .50302 .06722
FIGURE 19DISTRIBUTION HISTOGRAM OF QUALITY OF COMMUNICATION CONSTRUCT IN EXECUTION PHASE
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TABLE 43THE RESULTS OF INDEPENDENT-SAMPLES T-TEST FOR QUALITY OF COMMUNICATION IN CONCEPTUALIZATION-PLANNING PHASE COMPARISON
TABLE 44THE DESCRIPTIVES OF MANN-WHITNEY U TEST FOR QUALITY OF COMMUNICATION IN CONCEPTUALIZATION
-PLANNING PHASE OMPARISON
TABLE 45THE RESULTS OF MANN-WHITNEY U TEST FOR QUALITY OF COMMUNICATION
IN CONCEPTUALIZATION-PLANNING PHASE COMPARISON
4.1.3.2 Conceptualization and execution
Descriptives of the 2 phases are shown in Table 42 including sample size, mean, standard deviation, and standard error mean.
Table 46 presents the results of independent-samples t-test that also comprises the results of Levene's Test for Equality of Variances. According to the table, the variances of the phases is approximately equal and there is a significant difference in quality of communication between conceptualization and execution phases because the
significance level is lower than 0.05.
The results of Mann-Whitney U test together with its descriptives are presented in Table 47 and Table 48. Based on Table 48, there is no significant difference in quality of communication between conceptualization and execution phases of the projects because the significance level is greater than 0.05.
This can overrule the result of the t-test about a significant difference between the phases because conceptualization phase is not normal (because of high skewness and small sample size). Mann-Whitney U test is a test designed for comparing 2 sets of data that are either normally or not normally distributed. T-test results can be valid only for normal distribution. Therefore, the conclusion is that there is no significant difference
Independent Samples Test Levene's
Test for Equality of
Variances t-test for Equality of Means
F Sig. t df
Mann-Whitney U 737.500
Z -.435
Sig. (2-tailed) .664
a. Grouping Variable: Project phase
Ranks
Conceptualization 29 40.43 1172.5 Planning 54 42.84 2313.5
Total 83
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in quality of communication between conceptualization and execution phases of the projects.
TABLE 46THE RESULTS OF T-TEST FOR QUALITY OF COMMUNICATION IN CONCEPTUALIZATION-EXECUTION PHASES
TABLE 47THE DESCRIPTIVES OF MANN-WHITNEY
U TEST FOR QUALITY OF COMMUNICATION IN CONCEPTUALIZATION-EXECUTION PHASE COMPARISON
TABLE 48THE RESULTS OF MANN-WHITNEY U TEST FOR QUALITY OF COMMUNICATION IN
CONCEPTUALIZATION-EXECUTION COMPARISON
4.1.3.3 Planning and execution
Descriptives of the 2 phases are presented in Table 42 including sample size, mean, standard deviation, and standard error mean.
As mentioned before, the execution phase is considered not normal because the skewness and kurtosis are high, and the sample size is not large. Thus, the result the Mann-Whitney U test would be preferred if it does not match t-test results.
Table 49 presents the results of independent-samples t-test which also comprises the results of Levene's Test for Equality of Variances. According to the table, the variances of the phases is approximately equal and there is no significant difference in quality of communication between planning and execution phases of the projects because the significance level is greater than 0.05.
The results of Mann-Whitney U test together with its descriptives are presented in Table 50 and Table 51. Based on Table 51, there is a significant difference in quality of communication between planning and execution phases of the projects because the
Independent Samples Test Levene's Test
for Equality of
Variances t-test for Equality of Means
F Sig. t df
Sig.
(2-tailed) Mean
Difference Std. Error Difference
Conceptualization 29 36.59 1061.00 Execution 56 46.32 2594.00
Total 85
Test Statistics Quality of Communication
Mann-Whitney U 626.000
Z -1.724
Sig. (2-tailed) .085
a. Grouping Variable: Project phase
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significance level is lower than 0.05. More specifically, quality of communication is better in execution phase than in planning phase based on ‘mean ranks’ in Table 50.
This can overrule the result of the t-test about no significant difference between the phases because execution phase is not normal. Mann-Whitney U test is a test designed for comparing 2 sets of data that are either normally or non-normally distributed. T-test results can be valid only for normal distributions. Therefore, the conclusion is that there is a significant difference in quality of communication between planning and
execution phases of the projects.
TABLE 49THE RESULTS OF INDEPENDENT-SAMPLES T-TEST FOR QUALITY OF COMMUNICATION IN PLANNING
-EXECUTION PHASE COMPARISON
Independent Samples Test Levene's Test
for Equality of
Variances t-test for Equality of Means
F Sig. t df
OFCOMMUNICATION IN PLANNING-EXECUTION PHASE COMPARISON
TABLE 51THE RESULTS OF MANN-WHITNEY U TEST FOR QUALITY OF COMMUNICATION IN
PLANNING-EXECUTION PHASE COMPARISON