Statistical survey project

Statistical Survey ProjectBy: Jonathan Peñate andArnold Gonzalez

Our Survey Questions• 1. What is your gender?• 2. What grade are you in?• 3. What is your current age?• 4. How many people live in your household (including

yourself?) • 5. How many pets do you own?• 6. Do you like your parents?• 7. Are you for or against the legalization of marijuana? • 8. Are you in a school sport?• 9. If yes, how many?• 10. Are there any video game consoles in your house?• 11. How many TV’s are in your household?

Confidence Interval for Means

•Question 2•Question 3•Question 4•Question 5•Question 9•Question 11

Confidence Interval for Proportions

•Question 1•Question 6•Question 7•Question 8•Question 10

Confidence Interval for Mean Q.2

What grade are you in?X= 10.054, St. Dev= .882, n=92, df=91, z*=1.96

10.054-1.96(.882/sqt 92) = 9.87410.054-1.96(.882/sqt 92) = 10.234

Confidence Interval: (9.874, 10.234)

We are 95% confident that the true mean grade of the students is between 9.874 and 10.234


What is your current age?X= 15.543, St. Dev= 1.042, n=92, df=91, z*=1.96

15.543- 1.96(1.042/sqt 92) = 15.33015.543+ 1.96(1.042/.sqt 92) = 15.756


We are 95% confident that the true mean age of the students is between 15.330 and 15.756

Confidence Interval Q.4How many people live in your household?X= 5.889, St. Dev= 2.470, n=90, df= 89, z*=1.96

5.889- 1.96(2.470/sqt 90) = 5.3795.889+1.96(2.470/sqt 90) =6.399


We are 95% confident that the true mean of people living in the students’ households is between 5.379 and 6.399


How many pets do you own?X= 1.441, St. Dev= 1.515, n= 92, df= 91, z*= 1.96

1.441- 1.96(1.441/stq 92) = 1.314 1.441+ 1.96(1.441/stq 92)= 1.751


We are 95% confident that the true mean of pets owned by the students is between 1.314 and 1.751


How many school sports are you in?X= .359, St. Dev= .585, n=92, df= 91, z*1.96

.359- 1.96(.585/sqt 92) = .239

.359+ 1.96(.585/sqt 92)= .479

Confidence Interval: (.239, .479)

We are 95% that the true mean of students who are in a school sport is between .239 and .479


How many TV’s are in your household?X= 3.990, St. Dev= 1.600, n= 92, df= 91, z*= 1.96

3.990- 1.96(1.600/stq 92) = 3.6633.990+ 1.96(1.600/stq 92) = 4.317


We are 95% confident that the true mean of TV’s in students household is between 3.663 and 4.317

Confidence Interval for Proportion Q.1

What is your gender? p= malesp= .467, q= .532, z*=1.96, n=92

.467- 1.96*sqt[(.467)(.532)/92]= .365

.467+ 1.96*sqt[(.467)(.532)/92] = .569

Confidence Interval= (.365, .569)

We are 95% that the proportion of male students is between .365 and .569


Do you like you parents? p= .887, q= .123, z*= 1.96, n=89

.887- 1.96*sqt[(.822)(.178)/89)] = .822

.887+ 1.96*sqt[(.822)(.178)/89)] = .953


We are 95% confident that the true proportion of students who like their parents is between .822 and .953


Are you for or against marijuana? p= forp= .473, q= .527, z*= 1.96, n= 91

.473- 1.96*sqt[(.473)(.527)/(89)]= .369

.473+ 1.96*sqt[(.473)(.527)/(89)]= .575


We are 95% confident that the true proportion of students who are for marijuana are between .369 and .575


Are you in a school sport?p= .696, q= .304, z*= 1.96, n= 92

.696- 1.96*sqt[(.696)(.304)/92]= .376

.696+ 1.96*sqt[(.696)(.304)/92]= .583


We are 95% confident that the true proportion of students who are in a school sport is between .376 and .583

Confidence Interval from Proportion Q.10

Are there any video game consoles in your house?p= .867, q= .133, z*= 1.96, n= 90

.867- 1.96* sqt[(.867)(.133)/90]= .063

.867+ 1.96* sqt[(.867)(.133)/90]= .203


We are 95% confident that the true proportion of students who own have a video game console in their house is between .063 and .203

Hypothesis test for Q.1 vs Larger Study

1. Ho: p1 = p2; Ha: p1 ≠ p2

2. Randomness: The study is from the U.S. Census10% rule: The sample consists of less than 10% of the populationnp & nq= (.467)(92) > 10; (.499)(76899) > 10 np &nq= (.537)(92) > 10; (.501)(76899) > 10

3. We will conduct a 2-proportion z- test

4. Do the math… z= -.6128; p= .54

5. With such a high probability we fail to reject the null hypothesis. Therefore, there is not enough evidence to say that there is a difference between the two proportions.

Hypothesis test for Q.7 vs Larger Study

1. Ho: p1 = p2; Ha: p1 ≠ p2

2. Randomness: Randomness is not stated.10% rule: There is less than 10% of the total populationnp & nq= (.473)(91) > 10; (.527)(91) > 10np & nq= (.450)(828) > 10; (.500)(828) > 10

3. We will conduct a 2 proportion z- test

4. Do the math… z= -.4975; p= .618

5. With such a high probability, we fail to reject the Ho. There is not enough evidence to say that there is a difference between the two proportions.

Hypothesis on affirmative responses (Males vs Females) for Q.6

1. H0: μ of males = μ of females; Ha: μ of males ≠ μ of females.

2. Randomness: This was a random sample10% rule: We have less than 10% of the populationNearly normal: We can assume the data is normally distributed.

3. We will conduct a 2 sample t- test

4. Do the math… t= .083; df= 3.88, p= .937

5. With such a high probability, we fail to reject the null hypothesis. There is not enough evidence to say that there is a difference in the two sample means of affirmative answers.

Chi Squared Test for Homogeneity Q.6

Observed Yes No Omitted Total

Freshman 27 2 2 31

Sophomore 24 6 0 30

Junior 27 2 0 29

Senior 2 0 1 3

Total 80 10 3 93

Observed Yes No Omitted

Freshman 26.667 3.333 1

Sophomore 25.806 3.226 .9677

Junior 24.946 3.1183 .935

Senior 2.581 .323 .097

Chi Squared Test for Homogeneity Q.6 Continued

1. Ho: Responses are independent of grade levelHa: Responses are not independent of grade level

2. Randomness: We conducted a random sample10% condition: We have less than 10% of the population

3. We will conduct a X^2 test for homegeneity

4. Do the math… Chi^2 = 15.41; p= .22

5. Based on such a high probability, we cannot reject the null hypothesis. There is not enough evidence to say responses are not independent of grade level.

Sample study links

•http://www.maletofemaleratio.com/wiki/California-CA/Baldwin_Park.htm

http://www.maletofemaleratio.com/wiki/California-CA/Baldwin_Park.htm

http://www.maletofemaleratio.com/wiki/California-CA/Baldwin_Park.htm

Statistical survey project

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