1. By: Julia and Krista iTunes Song Lengths

2. Background Pop – Softer alternative to rock and roll aimed at youth market – Began in 1920s – Revolutionized by TV MTV Madonna and Michael Jackson

3. Background Rock – Blend of black rhythm-and-blues with white country- and-western – Originated in late 1940s and early 1950s United States and Great Britain Elvis and the Beatles

4. Background Country – originally found in the Southern United States and the Appalachian Mountains Blend of different styles of music found in these regions – Began to evolve in the 1920s Vernon Dalhart

5. Background R&B (Rhythm and Blues) – Originated in 1940s – Term originally used to describe recordings marketed to urban African Americans – Louis Jordan

6. Background Hip-Hop – Contains stylistic elements like rapping, DJing, sampling, scratching and beatboxing – Originated in South Bronx in New York in 1970s – DJ Kool Herc “Godfather” of hip- hop

7. Topic and Procedure Comparing song length to genre and artist gender – Genres: Pop, Rock, Country, R&B, Hip-hop Data from i tunes – First 30 non-repeating artists in each genre – Recorded length, genre and, artist gender Put song length in decimal form

8. Boxplots of Genre vs. Song Length

9. Genre vs. Song Length Analysis Country – Shape Slightly left skewed – Center Median 3.45 mins – Spread: Minimum: 2.583 mins Maximum: 4.35 mins No apparent outliers Hip-Hop Shape Slightly right skewed Center Median 3.925 mins Spread: Minimum: 2.95 mins Maximum: 5.567 mins No apparent outliers

10. Genre vs. Song Length Analysis Pop – Shape Roughly symmetric – Center Median 3.684 mins – Spread: Minimum: 3.017 mins Maximum: 4.817 mins No apparent outliers R&B Shape Symmetric Center Median 4.083 mins Spread: Minimum: 2.433 mins Maximum: 5.533 mins Apparent outliers at minimum and maximum

11. Genre vs. Song Length Analysis Rock – Shape Roughly symmetric – Center Median 4.017 mins – Spread: Minimum: 3.2 mins Maximum: 5.967 mins Apparent outliers at max, 5.933 mins, and 5.917 mins Conclusion Country songs generally shortest Rock songs generally longest Pop, hip-hop, and R&B, fall in the middle

12. Assumptions for 1-Sample T-test State 1. SRS 2. Normal population or n 30 Check 1.Not SRS but best sample so we proceeded with test 2.n=30 30

13. 1-Sample T-test for Pop Songs We reject the Ho because p-value < We have sufficient evidence that the true average length of a pop song is greater than 3.5 minutes.

14. 14 1-Sample T-Interval for Pop Song Lengths We are 99% confident that the mean length of a pop song is between 3.2526 and 3.7474 minutes.

15. Histograms of Song Length vs. Artist Gender

16. Song Length vs. Artist Gender Analysis Male – Slightly right skewed with center at about 4.4 minutes Female – Slightly right skewed with center at about 4.2 minutes Both – Uniform with center at approximately 4 minutes Conclusion – More male artists than female and mix of both genders – Least amount of mix of both gendered groups – Males had longest song lengths and both groups had shortest song lengths

17. 17 Check 1.Not SRS but best sample so we proceeded with test n=30 30 Assumptions for 1-Sample T-Test State 1. SRS 2. Normal population or n 30

18. 18 1-Sample T-Test for Male Artist Song Lengths We reject the Ho because p value < We have sufficient evidence that the true average length of a song by a male artist is less than 4.4 minutes.

19. 19 1-Sample T-Interval for Male Artist Song Lengths We are 95% confident that the mean length of a song by a male artist is between 3.7715 and 4.0172 minutes.

20. Bar Chart of Genre vs. Artist Gender

21. Genre vs. Artist Gender Analysis Country had most amount of mixed gender groups, rock had the least with 0 Rock was only genre with all male artists Pop had greatest amount of female artists – Followed by R&B

22. 22 Check 1.Not SRS but best sample so we proceeded with test 2.30(0.25)=7.5 10 30(0.75)=22.5 10  did not pass but we proceeded with test 3.population 300 1-Proportion Z-Test Assumptions State 1. SRS 2. np 10 n(1-p) 10 3.Population 10*n

23. 23 1-Proportion Z-Test for Female R&B Artists Ho: p=.25 Ha: p <.25 Z= = -0.634 P(z<-0.634)=0.2635 We fail to reject the Ho because p- value > We have sufficient evidence that the true percent of female R&B artists is equal to 25%.

24. 24 1-Proportion Z-Interval for Female R&B Artists We are 97% confident that the true percent of female R&B artists is between 4.152% and 35.848%.

25. 25 Application Population is pop, rock, hip-hop, R&B, and country songs We were able to compare the lengths of songs to each genre as well as the gender of the artist. We were also able to compare the gender of the artist to the each genre – Useful when searching for songs or burning CD’s We discovered that most songs are between 3.5 and 4.5 minutes Songs by male artists tended to be the longest All genres had more male than female artists

26. 26 Bias/Error Sample could have been better – SRS – Larger size – Repeating artists in different genres Only used i-tunes Rounded for song lengths in decimal form Rounded for null hypotheses

27. 27 Conclusions We thought that pop songs would be shortest and rock songs would be longest – Country had smallest average song length – R&B had largest average song length We expected the length of songs by male artists to be shortest and the length of songs by bands of both artists to be longest – Males actually had highest mean song length and bands of both had the smallest mean song length

28. Conclusions We expected pop songs to be by mostly female artists, hip-hop songs to be by males, and country and R&B songs to be by bands consisting of both – About half of pop was by females – Hip-hop, country, R&B, and rock were mostly by males – Few total song were by band with both genders We found that pop songs are between about 3.25 and 3.75 minutes The length of songs by male artists are between about 3.77 and 4.02 minutes Percentage of female R&B artists is between 4.1% and 35.8% 28