Stats

1. AP Statistics Survey Project Desiree Acevedo, Frank Palomarez, Paul Ortiz Mr. Eastvedt Period 4 June 4, 2011

2. Survey Questions Q1 - What grade are you in? Q2 - How old are you? Q3 - Are you male or female? Q4 - How many siblings do you have? Q5 - How many people live in your house? Q6 - How many days of the week do you typically get homework? Q7 - How many pairs of jeans do you own?

3. Questions continued …. Q8 - Which do you prefer to watch: College Football or Professional Football Q9 - What type of phone do you prefer: Touch screen or Full Keyboard Q10 - Which do you prefer: Fast Food or Home-made Food Q11 - Would you rather play videogames or physical sports?

4. Confidence Intervals for Means Question 1: Grade level of participants x= 9.93 s= 1.095 n= 84 df= 83 9.93 ± (T*)×(1.095/√84) = (9.70, 10.16) This confidence interval means that we are 95% confident that the true mean grade level of survey participants is between 9.70 and 10.16

5. Confidence Intervals for Means Question 2: Age of participants x= 15.27 s= 1.19 n= 84 df= 83 15.27 ± (T*)×(1.19/√84) = (15.02, 15.53) This confidence interval means that we are 95% confident that the true mean age of survey participants is between 15.02 and 15.53

6. Confidence Intervals for Means Question 4: Number of siblings participants have x= 2.63 s= 1.63 n= 84 df= 83 2.63 ± (T*)×(1.63/√84) = (2.28, 2.98) This confidence interval means that we are 95% confident that the true mean of number siblings of survey participants is between 2.28 and 2.98

7. Confidence Intervals for Means Question 5: Number of people in participant’s household x= 5.71 s= 2.39 n= 84 df= 83 5.71 ± (T*)×(2.39/√84) = (5.20, 6.23) This confidence interval means that we are 95% confident that the true mean of people in the household of survey participants is between 5.20 and 6.23

8. Confidence Intervals for Means Question 6: Day of week participants typically receive homework x= 4.44 s= 1.13 n= 73 df= 72 4.44 ± (T*)×(1.13/√73) = (4.17, 4.70) This confidence interval means that we are 95% confident that the true mean of days per week survey participants receive homework is between

9. Confidence Intervals for Means Question 7: Pairs of jeans participants own x= 10.91 s= 12.87 n= 67 df= 66 10.91 ± (T*)×(12.87/√67) = (7.77, 14.05) This confidence interval means that we are 95% confident that the true mean age of survey participants is between 7.77 and 14.05

10. Confidence Intervals for Proportions Question 3: Gender (p=female q=male) p= .548 q= .452 z*= 1.960 n= 84 .548 ± 1.960√((.548×.452)/84) = (.442, .654) This means that we are 95% confident that the true proportion of affirmative participants (females) is between .442 and .654

11. Confidence Intervals for Proportions Question 8: Watching NFL vs. NCAA Football (p = prefer NFL ; q = prefer NCAA) p= .868 q= .132 z*= 1.960 n= 76 .868 ± 1.960√((.868×.132)/76) = (.792, .944) This means that we are 95% confident that the true proportion of affirmative participants (prefer watching NFL) is between .792 and .944

12. Confidence Intervals for Proportions Question 9: Touch screen vs. Full Keyboard (p= Full keyboard q= Touch screen) p= .561 q= .439 Z*= 1.960 n= 82 .561 ± 1.960√((.561×.439)/82) = (.454, .668) This means that we are 95% confident that the true proportion of affirmative participants (prefer a full keyboard cell phone) is between .454 and .668

13. Confidence Intervals for Proportions Question 10: Fast food vs. Home-made (p= Fast Food q= Home-made) p= .296 q= .701 Z*= 1.960 n= 81 .296 ± 1.960√((.296×.701)/81) = (.197, .396) This means that we are 95% confident that the true proportion of affirmative participants (prefer fast food) is between .197 and .396

14. Confidence Intervals for Proportions Question 11: Videogames vs. Physical sports (p= Videogames q= Sports) p= .266 q= .742 Z*= 1.960 n= 79 .266 ± 1.960√((.266×.742)/79) = (.168, .364) This means that we are 95% confident that the true proportion of affirmative participants (prefer playing videogames) is between .168 and .364

15. Hypothesis Test: Question 6 How many days of the week do you typically get homework? “ … researchers say that American students have just the right amount of homework.” 1. Ho: x=4.44 Ha: x≠4.44 2. Assumptions/Conditions: *Randomness-our sample was randomly selected *10%-our sample is less than 10% of the student population *Distribution-we can assume that the sample is randomly distributed 3. We will conduct a 1 sample T-test 4. p-value= .612 5. With such a high p-value we cannot reject the null hypothesis. This means that we can assume that the average student receives homework about four to five days a week.

16. Larger Study Links Question 6- http://www.greatschools.org/students/homework-help/251-homework-is-too-much.gs Question 7- http://www.fashionwindows.net/2009/06/american-own-7-pairs-of-denim-jeans-on-average/ Question 8- http://www.cbssports.com/collegefootball/story/11212751

17. Males vs. Females: Question 11 Would you rather play videogames or physical sports? 1. Ho: proportion of males > proportion of females (prefer playing video games) Ha: proportion of males < proportion of females (prefer playing video games) 2. Assumptions/Conditions: *Randomness-our sample was randomly selected *10%-our sample is less than 10% of the student population *Distribution-we can assume that the sample is randomly distributed 3. We will conduct a 2-proportion Z-test 4. females = .256 males = .286 p-value = .322 5. With a high p-value we cannot reject the null hypothesis. This means that we can assume that the average teenage male prefers to play video games over physical sports than the average teenage female.