why do mallet mounié why do people buy...

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 = β0 + β1agei + β2friendsi + β3storei + β4budgeti

+β5shoebudgeti + β6couplei + β7jobi + β8childreni

+β9facebooki + β10pairsi + β11sexi + β12salesi + β13eventsi

+β14clothebudgeti + β15zonei

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