## Happy Easter Daniel

##### By Graham

Dear Daniel,

Yet another Easter is coming around the corner and I find myself thinking, once again, of you. There has, in fact, only ever been one Easter that we have spent together. It was the Easter of 2011. I remember I took you to Mass at Notre Dame au Sablon.

In all the years that have followed, I have always thought of you because Easter is a special time, a time for family.

Your little sister Daphne is thriving. She can’t yet crawl or walk but she scoots around on her bum – very cute. The creche gave her a gift of a few chocolate eggs for Easter but I’m afraid she’s too young to enjoy those kinds of treats (so instead she will have to make do with mushy vegetables and milk!)

I have an Easter egg here for you but as I have no way of giving it to you, I’m afraid I will have to donate it or eat it myself.

Still I hope you get some nice chocolate (but not too much!). I will be thinking of you.

Love,

Category: Dear Daniel

As with birth rates, we use data for 4 categories of countries from 1990 to 2015 (100 observations total). We have two explanatory variables, AGE and Y, where AGE is defined as the percentage of the population aged over 65 and Y is per capita GDP.

After eyeballing the scattergrams, we test the following functional form:

d = (minY^a)/Y^a * (1/AGE^g)

Where minY is the constant equal to the smallest value of Y in the series.

Logarithmic transformation gives:

ln(d) = ln(minY^a) – a*ln(Y) – g*ln(AGE)

which we test on the data using OLS. Here are the results:

Intercept coefficient: 7.37384
t-Stat: 20.4011

Y coefficient: -1.01444
t-Stat: -13.1059

AGE coefficient: 2.0097
t-Stat: 11.5208

The estimated intercept is a good, but not perfect, approximation of ln(minY^a)

Here are the fitted against actual values of the scattergram for death rate against per capita GDP:

While the results are not as good as with the birth rates calculations, it is nevertheless a good enough fit and the explanatory variables have a strong enough confidence factor to be usable in our estimations.

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We begin by examining the scatter of data for 100 observations of per capita GDP and per capita emissions for 4 categories of countries, over 25 years (1990 – 2015).

The scatter suggests a cubic functional form, so we test:

GHG = a + b*Y + c*Y^2 + d*Y^3

where GHG are per capita emissions of GHG, and Y is per capita GDP.

The results from OLS regression are:

coefficient a: 1090
t-stat a: 3.06

coefficient b: 0.709310153
t-Stat b: 8.241453

coefficient c: -0.0000047025
t-Stat c: -1.01233

coefficient d: -0.000000000105314
t-Stat d: -1.47005

While the t-scores on the squared and cubed terms are low, the number of observations are also limited.

Here is the plot of the fitted against actual values:

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