Energy Drinks!

Energy Drinks!Energy Drinks!

By: Michael Williams, Erica Lee,Erica Kim, and Davis SongBy: Michael Williams, Erica Lee,Erica Kim, and Davis Song

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Goal or PurposeGoal or Purpose

Our goal is to see if there is acorrelation between the sex ofOur goal is to see if there is acorrelation between the sex of

Castro Valley High School seniorsCastro Valley High School seniors

and whether they like energyand whether they like energy

drinks or not.drinks or not.

Experimental DesignExperimental Design

-Experiment to provide evidence if there’s adifference in proportions between seniorboys and girls who prefer energy drinks-Experiment to provide evidence if there’s adifference in proportions between seniorboys and girls who prefer energy drinks

-Past experience--Past experience-

-Older students prefer energy drinks thanyounger students-Older students prefer energy drinks thanyounger students

-Male students prefer energy drinks morethan female students-Male students prefer energy drinks morethan female students

ProcessProcess

- Created a poll anddistributed it randomlyto all seniors in theclasses we visited- Created a poll anddistributed it randomlyto all seniors in theclasses we visited

-Polled only seniors atCVHS in 7th period-Polled only seniors atCVHS in 7th period

-Ensured that nostudent was polledtwice-Ensured that nostudent was polledtwice

FORMFORM

Gender (circle one) Male FemaleGender (circle one) Male Female

Preferred Beverage (circle one)Preferred Beverage (circle one)

CoffeeJuiceCoffeeJuice

Energy DrinkSodaEnergy DrinkSoda

WaterTeaWaterTea

Process Continued…Process Continued…

-To determine whether the subjectspreferred energy drinks we listed“energy drinks” among otherbeverages rather than asking if theylike energy drinks or not-To determine whether the subjectspreferred energy drinks we listed“energy drinks” among otherbeverages rather than asking if theylike energy drinks or not

-7th period classes- example:Government and Economics classesto ensure mostly seniors-7th period classes- example:Government and Economics classesto ensure mostly seniors

-If juniors were present, they did notreceive a form-If juniors were present, they did notreceive a form

Process Continued…Process Continued…

-Most students filled out forms correctly-Most students filled out forms correctly

-Collected 117 forms-Collected 117 forms

-1 filled out incorrectly -1 filled out incorrectly

-2 wrote their own drinks (“tea” and“milk”) because 1st preferred notpresent -2 wrote their own drinks (“tea” and“milk”) because 1st preferred notpresent

Errors in ProcessErrors in Process

-We had to randomly select 55forms out of our 117, because ourpopulation was too small and oursample size was too big.-We had to randomly select 55forms out of our 117, because ourpopulation was too small and oursample size was too big.

-To do so, we used the randomnumbers chart-To do so, we used the randomnumbers chart

BiasBias

-Not a true SRS, not allseniors had an equalchance of being chosen-Not a true SRS, not allseniors had an equalchance of being chosen

*Not all seniors have a 7th*Not all seniors have a 7th

DataData

MaleMale

FemaleFemale

CoffeeCoffee

Energy DrinkEnergy Drink

1212

WaterWater

JuiceJuice

SodaSoda

TeaTea

MilkMilk

TotalTotal

2727

2828

Proportion ofSeniors Whoprefer EnergyDrink:

Male= .4444

Female= .1786

2-Prop Z Test2-Prop Z Test

H0: p1 = p2 where p1 = proportion ofmale seniors at Castro Valley Highwho prefer energy drinksH0: p1 = p2 where p1 = proportion ofmale seniors at Castro Valley Highwho prefer energy drinks

HA: p1 > p2 and p2 = proportion offemale seniors at Castro Valley Highwho prefer energy drinksHA: p1 > p2 and p2 = proportion offemale seniors at Castro Valley Highwho prefer energy drinks

ztest=-2.5036, p-value=.0123ztest=-2.5036, p-value=.0123

Reject H0 if p-value < αReject H0 if p-value < α

Calculations for percentagesCalculations for percentages

ConditionsConditions

All are 5 or larger, we are safe using a 2-sample z-procedure

ConditionsConditions

-The population is at least 10times as large as the sample.-The population is at least 10times as large as the sample.

Castro Valley’s seniorpopulation is 554, and oursample size is 55.Castro Valley’s seniorpopulation is 554, and oursample size is 55.

(55)(10)=550(55)(10)=550

554 > 550 seniors at CVHS554 > 550 seniors at CVHS

Z-test statisticZ-test statistic

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AnalysisAnalysis

We reject H0 at the 5% level(p=.01646). We reject H0 at the 5% level(p=.01646).

If we do in fact reject H0 ,thenthe proportion of male seniorsat CVHS prefer energy drinksover the proportion of femaleseniors at CVHS. If we do in fact reject H0 ,thenthe proportion of male seniorsat CVHS prefer energy drinksover the proportion of femaleseniors at CVHS.

2-prop Z Int.Conditions2-prop Z Int.Conditions

All are 5 or larger, therefore we aresafe using a 2-proportion z interval.

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95% Confidence Interval95% Confidence Interval

Confidence interval: (.0308,.5009)

AnalysisAnalysis

We are 95% confident that the truemean proportion(Proportion of maleswho prefer energy drinks- Proportionof females who prefer energy drinks)is between .0308 and .5009.We are 95% confident that the truemean proportion(Proportion of maleswho prefer energy drinks- Proportionof females who prefer energy drinks)is between .0308 and .5009.

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ConclusionConclusion

Our experiment to decide whether ornot male seniors at CVHS preferenergy drinks more than femaleseniors at CVHS seemed to confirmthat a larger proportion or maleseniors prefer energy drinks thanfemale seniorsOur experiment to decide whether ornot male seniors at CVHS preferenergy drinks more than femaleseniors at CVHS seemed to confirmthat a larger proportion or maleseniors prefer energy drinks thanfemale seniors

Conclusion Significance TestConclusion Significance Test

Significant at 5% levelSignificant at 5% level

Rejected hypothesis that the twoproportions are equalRejected hypothesis that the twoproportions are equal

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Conclusion Confidence IntervalConclusion Confidence Interval

-Male proportion likely to be largerbecause the left tail of the distributionnot covered by the interval (2.5%) isstill over zero meaning the maleproportion would still be larger thanthe female proportion. The right tailwould still mean a larger maleproportion-Male proportion likely to be largerbecause the left tail of the distributionnot covered by the interval (2.5%) isstill over zero meaning the maleproportion would still be larger thanthe female proportion. The right tailwould still mean a larger maleproportion

-This coincides with thesignificance results of .0165-This coincides with thesignificance results of .0165

Final ConclusionFinal Conclusion

-We feel the survey we created,distributed, and analyzed shows agreater male proportion of seniorsover female who prefer energydrinks.-We feel the survey we created,distributed, and analyzed shows agreater male proportion of seniorsover female who prefer energydrinks.

-Data could be used for marketing.-Data could be used for marketing.

*More male oriented energydrinks *More male oriented energydrinks