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  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    Why do people buy shoes?And what are the differences beetween boys and girls?

    Bérénice Mallet - Floriane Mounié

    Econometrics : Application Project

    May 21st 2014

    1/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    Introduction

    What individual characteristics can influence our shoespurchases ?

    2/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    IntroductionFirst steps

    We had to :1 Choose some individual characteristics that might

    influence shoe purchase

    2 Realise a survey3 Create a data base for Eviews with the survey answers

    3/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    IntroductionFirst steps

    We had to :1 Choose some individual characteristics that might

    influence shoe purchase2 Realise a survey

    3 Create a data base for Eviews with the survey answers

    3/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    IntroductionFirst steps

    We had to :1 Choose some individual characteristics that might

    influence shoe purchase2 Realise a survey3 Create a data base for Eviews with the survey answers

    3/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    IntroductionExplanatory variables

    Explanatory Variables Expected EffectAge =Friends +Store =Budget +Shoe Budget +Couple -Job +Children -Facebook +Pairs +Sex -Sales +Events +Clothe Budget +Zone + 4/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    First modelA linear model : First Equation

    At first, we tried to modelise shoe purchase with lineardependance on all other variables.

    EQU 01

    ̂purchasei = β̂0 + β̂1agei + β̂2friendsi + β̂3storei + β̂4budgeti

    +β̂5shoebudgeti + β̂6couplei + β̂7jobi + β̂8childreni+β̂9facebooki + β̂10pairsi + β̂11sexi + β̂12salesi + β̂13eventsi

    +β̂14clothebudgeti + β̂15zonei

    5/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    First modelLinear Regression Output

    6/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    First modelReal effects

    Explanatory Variables Expected Effect Real EffectAge = -Friends + -Store + -Budget + =Shoe Budget + +Couple - +Job + +Children - +Facebook + -Pairs + +Sex - -Sales + -Events + +Clothe Budget + +Zone + + 7/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    First modelR-squared

    For this estimation, R-squared has a value of 0.562We will try to improve this by not taking into accountsome redundant characteristics.The correlation matrix reveals that some characteristicsare strongly correlated, and so redundant.

    8/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    First modelCorrelation matrix

    9/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    First modelCorrelated variables

    Two variables were removed from the model :Age was to much correlated to budgetChildren was also correlated to budget

    10/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    First modelWald Test

    Some variables might not have a significant influence on shoepurchase. We performed a Wald test on the nullity hypothesisof the βk .

    11/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    First modelInsignificant Variable

    A high p-value means that the nullity hypothesis is notrejected. Four variables are removed of the model :

    StoreFacebookZone

    12/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    First modelSecond Equation

    Here is the new linear equation :

    EQU 02

    ̂purchasei = 0.158 − 0.0004friendsi − 0.0001budgeti+0.004shoebudgeti + 0.304couplei + 0.236job + 0.069pairsi

    −0.0337sexi − 0.0001isales + 0.063eventsi+0.0006clothebudgeti

    13/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    First modelNormality, Quantile Quantile Plot

    14/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    Women’s ModelDistinct Population

    One of the reasons our model is not exactly accurate migth bethat boys and girls have a very different behavior for shoespurchase.

    There are two different populations, so we need to build adifferent model for women !

    15/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    Women’s ModelDistinct Population

    One of the reasons our model is not exactly accurate migth bethat boys and girls have a very different behavior for shoespurchase.

    There are two different populations, so we need to build adifferent model for women !

    15/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    Women’s ModelLinear Regression

    Using the same variable, another linear regression wasperformed focusing on women population. Using the samemethods,

    The variables Age, Children and Clothebudget areremoved because of correlation.Store, Facebook, Couple and Zone are removed becausethey are insgnificant.

    16/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    Women’s ModelWomen’s Equation

    Here is the final linear equation :

    EQU 03

    ̂purchasei = 0.0187 − 0.0011friendsi − 0.00001budgeti

    +0.0083shoebudgeti + 0.524job + 0.0509pairsi−0.0072sales + 0.0917eventsi

    A few remarks :Of course, women buy a lot more shoes than menGirls are less sensible than boys to budget constraintThey buy a higher proportion of their shoes during sales.

    17/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    Women’s ModelHeteroscedasticity

    The White’s test result is that we do reject theheteroscedasticity hypothesis. (p > 0.05)The model can be considered homoscedastic.

    18/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    Women’s ModelError

    The Jarque-Bera’s test result (p > 5 % and Stat < 6)indicates that the residual error can be identified as following anormal law.

    19/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    Women’s ModelQuantile Quantile Plot

    Comparison with normal law :

    20/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    Conclusion

    Conclusion

    The final model reveals that the more influcial charateristics onwomen’s purchase are :

    her budget for shoeswether she has a job or notthe number of pairs she already ownsthe number of activities an leisures she have

    But more surprisingly neither the place of living nor the beingin a relationship have an impact on shoe purchase.

    21/22

  • Why dopeople buy

    shoes?

    Mallet Mounié

    Introduction

    First model

    Women’sModel

    ConclusionThank you for your attention !

    22/22

    IntroductionFirst modelWomen's ModelConclusion