Descriptive Statistics
Juice dataset (OJ). For simplicity, the products and stores of the dataset represent the whole market.
Description
The data contains 1070 purchases where the customer either purchased Citrus Hill or Minute Maid Orange Juice. A number of characteristics of the customer and product are recorded.
A data frame with 1070 observations on the following 18 variables.
Purchase
|
A factor with levels CH and MM indicating whether the customer purchased Citrus Hill or Minute Maid Orange Juice |
WeekofPurchase | Week of purchase |
StoreID | Store ID |
PriceCH | Price charged for CH |
PriceMM | Price charged for MM |
DiscCH | Discount offered for CH |
DiscMM | Discount offered for MM |
SpecialCH | Indicator of special on CH |
SpecialMM | Indicator of special on MM |
LoyalCH | Customer brand loyalty for CH |
SalePriceMM | Sale price for MM |
SalePriceCH | Sale price for CH |
PriceDiff | Sale price of MM less sale price of CH |
Store7 | A factor with levels No and Yes indicating whether the sale is at Store 7 |
PctDiscMM | Percentage discount for MM |
PctDiscCH | Percentage discount for CH |
ListPriceDiff | List price of MM less list price of CH |
STORE | Which of 5 possible stores the sale occured at |
Basic summary statistics of the OJ data frame
## Purchase WeekofPurchase StoreID PriceCH PriceMM
## CH:653 Min. :227.0 Min. :1.00 Min. :1.690 Min. :1.690
## MM:417 1st Qu.:240.0 1st Qu.:2.00 1st Qu.:1.790 1st Qu.:1.990
## Median :257.0 Median :3.00 Median :1.860 Median :2.090
## Mean :254.4 Mean :3.96 Mean :1.867 Mean :2.085
## 3rd Qu.:268.0 3rd Qu.:7.00 3rd Qu.:1.990 3rd Qu.:2.180
## Max. :278.0 Max. :7.00 Max. :2.090 Max. :2.290
## DiscCH DiscMM SpecialCH SpecialMM
## Min. :0.00000 Min. :0.0000 Min. :0.0000 Min. :0.0000
## 1st Qu.:0.00000 1st Qu.:0.0000 1st Qu.:0.0000 1st Qu.:0.0000
## Median :0.00000 Median :0.0000 Median :0.0000 Median :0.0000
## Mean :0.05186 Mean :0.1234 Mean :0.1477 Mean :0.1617
## 3rd Qu.:0.00000 3rd Qu.:0.2300 3rd Qu.:0.0000 3rd Qu.:0.0000
## Max. :0.50000 Max. :0.8000 Max. :1.0000 Max. :1.0000
## LoyalCH SalePriceMM SalePriceCH PriceDiff Store7
## Min. :0.000011 Min. :1.190 Min. :1.390 Min. :-0.6700 No :714
## 1st Qu.:0.325257 1st Qu.:1.690 1st Qu.:1.750 1st Qu.: 0.0000 Yes:356
## Median :0.600000 Median :2.090 Median :1.860 Median : 0.2300
## Mean :0.565782 Mean :1.962 Mean :1.816 Mean : 0.1465
## 3rd Qu.:0.850873 3rd Qu.:2.130 3rd Qu.:1.890 3rd Qu.: 0.3200
## Max. :0.999947 Max. :2.290 Max. :2.090 Max. : 0.6400
## PctDiscMM PctDiscCH ListPriceDiff STORE
## Min. :0.0000 Min. :0.00000 Min. :0.000 Min. :0.000
## 1st Qu.:0.0000 1st Qu.:0.00000 1st Qu.:0.140 1st Qu.:0.000
## Median :0.0000 Median :0.00000 Median :0.240 Median :2.000
## Mean :0.0593 Mean :0.02731 Mean :0.218 Mean :1.631
## 3rd Qu.:0.1127 3rd Qu.:0.00000 3rd Qu.:0.300 3rd Qu.:3.000
## Max. :0.4020 Max. :0.25269 Max. :0.440 Max. :4.000
(Answers max 30 characters per question)
- How many stores are available in the dataset?
- How many weeks does the dataset cover?
- Which one of the two orange juice products is more expensive on average?
- Which one of the two orange juice products is more often on special offer?
- Which one of the two orange juice products has the greatest discount percentage on average?
- How are prices, discounts, and sales prices related in the dataset?
Sale prices histograms for the Citrus Hill and Minute Maid Orange Juices.
(Answers max 500 characters per question)
- Based on the above summary and histograms, what is your initial assessment concerning the quality relationship between the two products?
- Based on the above, what is your assessment concerning the pricing strategies followed by the firms in the market?
Product Market Shares
Examine the market shares for each orange juice product and the market power of the producing firms.
summary of sharesCH and sharesMM data.
## CH MM## Min. 0.2121212 0.1250000## 1st Qu. 0.5000000 0.2794444## Median 0.6372180 0.3627820## Mean 0.6057768 0.3942232## 3rd Qu. 0.7205556 0.5000000## Max. 0.8750000 0.7878788
- Based on the above, which product has the larger market share on average? How do you interpret the result?
(Answers max 500 characters per question)
- Based on the above, which product has more weekly purchases more often? How do you interpret the result? Is this result in line with your interpretation of market shares?
- Do you observe a date at which the behavior of the purchases of the two products changes? Are your interpretations in questions 1 and 2 driven by the whole sample? Are they driven or from a subset of dates in the sample?
Market Estimation
Estimating a market-clearing model using panel data and examining the resulting demand and supply elasticities for both Citrus Hill and Minute Maid Orange Juice.
Estimates of the market model for the Citrus Hill data.
## Equilibrium Model for Markets in Equilibrium:## Demand RHS : D_SalePriceCH + D_SalePriceMM + D_WeekofPurchase## Supply RHS : S_SalePriceCH + S_WeekofPurchase + S_SpecialCH## + S_StoreID## Market Clearing : NoPurchases = D_NoPurchases = S_NoPurchases## Shocks : Correlated## Nobs : 653## Sample Separation : Not Separated## Quantity Var : NoPurchases## Price Var : SalePriceCH## Key Var(s) : StoreID, WeekofPurchase## Time Var : WeekofPurchase## ## Maximum likelihood estimation:## Method : BFGS## Convergence Status : success## Starting Values :## D_SalePriceCH D_CONST D_SalePriceMM D_WeekofPurchase ## -27.285550 26.221912 1.888320 0.095356 ## S_SalePriceCH S_CONST S_WeekofPurchase S_SpecialCH ## 33.089373 -58.766139 0.007735 11.647788 ## S_StoreID2 S_StoreID3 S_StoreID4 S_StoreID7 ## -1.378343 -4.403546 -4.351425 4.342338 ## D_VARIANCE S_VARIANCE RHO ## 11.914957 23.541607 -0.202668 ## ## Coefficients:## Estimate Std. Error z value Pr(>|z|) ## D_SalePriceCH -31.55390901 1.52064629 -20.750328 1.217585e-95 ***## D_CONST 32.50536839 3.54508561 9.169135 4.768300e-20 ***## D_SalePriceMM 2.48326026 0.67694951 3.668309 2.441596e-04 ***## D_WeekofPurchase 0.09616766 0.01025188 9.380487 6.566858e-21 ***## S_SalePriceCH 27.03270999 1.18338671 22.843513 1.695317e-115 ***## S_CONST -50.97312757 1.33755482 -38.109188 0.000000e+00 ***## S_WeekofPurchase 0.01678551 0.01346038 1.247031 2.123860e-01 ## S_SpecialCH 9.96840294 0.55663702 17.908264 1.016563e-71 ***## S_StoreID2 -0.83092819 0.61990117 -1.340420 1.801087e-01 ## S_StoreID3 -2.68217094 0.71065990 -3.774198 1.605235e-04 ***## S_StoreID4 -2.24175614 0.67065001 -3.342662 8.297898e-04 ***## S_StoreID7 5.43156610 0.57886201 9.383179 6.401268e-21 ***## D_VARIANCE 14.18923357 1.24852964 11.364755 6.263989e-30 ***## S_VARIANCE 18.72063266 1.26470325 14.802391 1.413657e-49 ***## RHO -0.26716528 0.05220004 -5.118105 3.086211e-07 ***## —## Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ‘ 1## ## -2 log L: 1986.905
Corresponding plot
Estimates the market model for the Minute Maid Orange Juice data.
## Equilibrium Model for Markets in Equilibrium:## Demand RHS : D_SalePriceMM + D_SalePriceCH + D_WeekofPurchase## Supply RHS : S_SalePriceMM + S_WeekofPurchase + S_SpecialMM## + S_StoreID## Market Clearing : NoPurchases = D_NoPurchases = S_NoPurchases## Shocks : Correlated## Nobs : 417## Sample Separation : Not Separated## Quantity Var : NoPurchases## Price Var : SalePriceMM## Key Var(s) : StoreID, WeekofPurchase## Time Var : WeekofPurchase## ## Maximum likelihood estimation:## Method : BFGS## Convergence Status : success## Starting Values :## D_SalePriceMM D_CONST D_SalePriceCH D_WeekofPurchase ## -4.05336 4.86909 2.29706 0.00738 ## S_SalePriceMM S_CONST S_WeekofPurchase S_SpecialMM ## 12.81679 -18.01234 -0.01540 5.37839 ## S_StoreID2 S_StoreID3 S_StoreID4 S_StoreID7 ## 0.17442 -1.46987 -3.31595 1.07991 ## D_VARIANCE S_VARIANCE RHO ## 2.73589 16.22803 0.32686 ## ## Coefficients:## Estimate Std. Error z value Pr(>|z|) ## D_SalePriceMM -4.16029559 0.655198389 -6.3496731 2.157729e-10 ***## D_CONST 5.03677872 1.464823191 3.4384892 5.849699e-04 ***## D_SalePriceCH 2.35378804 0.812712511 2.8962124 3.776967e-03 **## D_WeekofPurchase 0.00710339 0.005344794 1.3290296 1.838382e-01 ## S_SalePriceMM 11.20393559 0.460852032 24.3113512 1.486977e-130 ***## S_CONST -15.38509574 0.564571536 -27.2509235 1.620499e-163 ***## S_WeekofPurchase -0.01014977 0.004994532 -2.0321763 4.213581e-02 *## S_SpecialMM 4.60431309 0.527088316 8.7353731 2.428532e-18 ***## S_StoreID2 -1.01396030 0.619718139 -1.6361637 1.018053e-01 ## S_StoreID3 -2.33929111 0.621746380 -3.7624523 1.682554e-04 ***## S_StoreID4 -2.45869406 0.841625287 -2.9213643 3.485021e-03 **## S_StoreID7 0.13272188 0.645712370 0.2055434 8.371476e-01 ## D_VARIANCE 2.73202247 0.193621293 14.1101344 3.289505e-45 ***## S_VARIANCE 13.97708062 0.574493295 24.3294060 9.578197e-131 ***## RHO 0.40122479 0.104070105 3.8553318 1.155728e-04 ***## —## Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ‘ 1## ## -2 log L: 1533.975
Corresponding plot
(Answers max 500 characters per question)
- What are the signs of the demand and supply price coefficients? Are they as expected?
- Which product’s demand is more elastic? How do you interpret this?
- Which product’s supply is more elastic? How do you interpret this?
- What are the signs of the estimated cross-price demand coefficients? Are the products substitutes or complements?