Figure 3.13: Tukey graph of MUSHRA means
Analysis
The visual representation of all the data reveals that LC3 (64) sticks out as the lowest rated sample by a notable margin.
An ANOVA test with an α-value of 0.05 was performed to investigate if there is a significant difference. It showed an F-statistic of 22.69 with a P-value of 0.0. This result indicates that there is a significant difference in perceived audio quality but the test does not specify between which pairs.
A Tukey’s range test was performed to compare each pair to see if they differ from one another, and it showed no significant difference between the bitrates except for LC3 (64) that differed from all other samples.
Hence the null hypothesis for RQ2 is rejected and thus the following is true: There is a significant difference in perceived audio quality between the selected pairs of codecs and bitrates.
3.3Survey (quantitative)
The following figures represent the level of satisfaction for audio quality in both interactive and non-interactive scenarios.
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Figure 3.14: Satisfaction score, interactive (raw data)
Figure 3.15: Satisfaction score, non-interactive (raw data)
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The remaining figures was created without filtering, such as removing outliers, of the raw data (Figure 3.14 & 3.15).
Figure 3.16: Satisfaction score means, with SD
The SD for the rated intervals (Figure 3.16) varies between 0.45 - 1.15 for the interactive scenarios, as well as 0.32 - 0.96 for the non-interactive scenarios.
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Figure 3.17: Satisfaction score means, with SE
The SE for the rated intervals (Figure 3.17) is quite consistent with a variation between 0.10 - 0.27 for the interactive scenarios, as well as 0.07 - 0.23 for the non-interactive scenarios.
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Figure 3.18: Satisfaction score means, with a CI of 95%
The CI of 95% for the scenarios overlap in each rated interval (Figure 3.18).
Analysis
The visual representation of the data reveals that there should be no significant difference between the interval pairs.
To investigate if there is a significant difference, an ANOVA test with an α-value of 0.05 was performed for the five intervals.
•00-19 showed an F-statistic of 3.27 with a P-value of 0.08.
•20-39 showed an F-statistic of 1.09 with a P-value of 0.30.
•40-59 showed an F-statistic of 1.58 with a P-value of 0.22.
•60-79 showed an F-statistic of 0.15 with a P-value of 0.70.
•80-99 showed an F-statistic of 0.11 with a P-value of 0.08.
Hence the null hypothesis for RQ3 is accepted and thus the following is true: There is no significant difference in attitude toward audio quality in a real-time interactive scenario compared to a non-interactive scenario.
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