Merge pull request #313 from QuantEcon/fix-mccall-cor

[mccall_correlated] Fix Standard Deviation Calculation

Author: jstac

lectures/kesten_processes.md

@@ -26,7 +26,7 @@ This lecture is accelerated via [hardware](status:machine-details) that has acce
 
 Free GPUs are available on Google Colab. To use this option, please click on the play icon top right, select Colab, and set the runtime environment to include a GPU.
 
-Alternatively, if you have your own GPU, you can follow the [instructions](https://github.com/google/jax#pip-installation-gpu-cuda) for installing JAX with GPU support.
+Alternatively, if you have your own GPU, you can follow the [instructions](https://github.com/google/jax) for installing JAX with GPU support.
 ```
 
 ```{index} single: Linear State Space Models

lectures/mccall_correlated.md

@@ -207,7 +207,7 @@ class JobSearch:
 
         # Set up grid
         z_mean = d / (1 - ρ)
-        z_sd = np.sqrt(σ / (1 - ρ**2))
+        z_sd = σ / np.sqrt(1 - ρ**2)
         k = 3  # std devs from mean
         a, b = z_mean - k * z_sd, z_mean + k * z_sd
         self.z_grid = np.linspace(a, b, grid_size)

lectures/mle.md

@@ -35,7 +35,7 @@ involves specifying a class of distributions, indexed by unknown parameters, and
 
 The benefit relative to linear regression is that it allows more flexibility in the probabilistic relationships between variables.
 
-Here we illustrate maximum likelihood by replicating Daniel Treisman's (2016) paper, [Russia's Billionaires](https://pubs.aeaweb.org/doi/pdfplus/10.1257/aer.p20161068), which connects the number of billionaires in a country to its economic characteristics.
+Here we illustrate maximum likelihood by replicating Daniel Treisman's (2016) paper, [Russia's Billionaires](https://www.aeaweb.org/articles?id=10.1257/aer.p20161068), which connects the number of billionaires in a country to its economic characteristics.
 
 The paper concludes that Russia has a higher number of billionaires than
 economic factors such as market size and tax rate predict.