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Average Length of Top 100 Songs on iTunes
Generated Dec 4, 2012 by n.anisko

Nathan Anisko and Eric Anderson

Introduction

Is the average length of a top 100 song on iTunes 180 seconds? We predicted that the average length of a top 100 song on iTunes is not equal to 180 seconds. Scientists have found that 180 seconds is where bloat starts to set in. The population that we intend for our study to represent is the top 100 songs on iTunes. The variable that we obtained during our data collection was the song length in seconds.

Methods

We collected our data from the Top 100 Songs section of the iTunes Store. We selected data to include in our sample by randomly choosing 30 of the top 100 songs. To avoid bias in our sample, we used a random number generator that included the numbers 1 through 100, which represented the rankings of the songs, to select 30 different songs. We believe the sample we obtained was representative of the population because it was random and included over a quarter of the population. We conducted a one-sample t-test to analyze our data.

Results

Our confidence level is 95% and our significance level is 5%. The point estimate is 226.933. The margin of error is 11.762. The degrees of freedom is 29. The Confidence Interval is (215.171, 238.695). We are 95% confident that the average song length of a top 100 song on iTunes falls within the interval of 215.171 to 238.695 seconds.

Conclusions

The average length of a top 100 song on iTunes does not equal 180 seconds. Our analyses support our expected findings. The 95% Confidence Interval does not contain the assumed value of 180 seconds. This challenge is statistically significant at the 5% significance level. As a result of our study, we can draw the conclusion that the average length of a top 100 song on iTunes is much greater than 180 seconds. From this project, we learned that the top 100 songs on iTunes contain a wide range of genres, the song lengths can differ by a large amount, and the one-sample t-test is useful to determine whether a stated value is accurate among a population.

Result 1: Song Lengths Table   [Info]
Summary statistics:
 Column Mean Std. Dev. Min Max Q1 Q3 n Median Song Length (Seconds) 226.93333 31.501432 163 291 208 241 30 223

Result 2: Song Lengths Chart   [Info]