Update for Week 2

Added material to the index page for week 2, and slightly modified the text.

docs/Week2.md

@@ -15,7 +15,7 @@ This week we are going to be discussing how to combine measurements and the impo
 
 When taking data or reading through scientific results, you will encounter measurements of the same parameter which were taken by different instruments, or where you don't have access to the raw data. One approach to combining multiple measurements is using a weighted average, where the weights depend on the uncertainties on each measurement. The first notebook will explore this approach and how it compares to taking the "true mean".
 
-The second notebook will explore Poisson statistics. The Poisson distribution describes the number of random events which occur in a fixed period of time, where each event is independently and has a fixed average rate. This can be applied to radioactive decays, the earthquakes, or when our wifi randomly seems to go down. 
+The second notebook will explore Poisson statistics. The Poisson distribution describes the number of random events which occur in a fixed period of time, where each event is independent and there is a fixed average rate. This can be applied to collecting photons in cameras or other photodetectors, radioactive decays, earthquakes, or when our wifi randomly seems to go down.
 
 ## Scientific context and resources
 

docs/index.md

@@ -46,66 +46,66 @@ This is sufficient for the notes, but to do the tutorials you will need to downl
   * [Notebook 2: "Dice rolls and histograms"](https://github.com/KIPAC/Physics89L/blob/main/nb/01_02_Dice_Rolls_and_Histograms.ipynb)
   * [Notebook 3: "Hubble constant measurements"](https://github.com/KIPAC/Physics89L/blob/main/nb/01_03_Hubble_Measurements.ipynb)
 
-<!---
+
 * Notes for Week 2: 
   * Topics: Weighted averages and Poisson statistics
   * [Background and reference](Week2.md)
   * [Notebook 1: "Hubble constant uncertainties"](https://github.com/KIPAC/Physics89L/blob/main/nb/02_01_Hubble_Constant_Uncertainties.ipynb)
   * [Notebook 2: "Counting muons"](https://github.com/KIPAC/Physics89L/blob/main/nb/02_02_Counting_Muons.ipynb)
---->
 
-<!---
+
+<!--
 * Notes for Week 3: 
   * Topics: Error propagation
   * [Background and reference](Week3.md)
   * [Notebook 1: "Propagation of errors"](https://github.com/KIPAC/Physics89L/blob/main/nb/03_01_Propagation_of_errors.ipynb)
   * [Notebook 2: "More propagation of errors"](https://github.com/KIPAC/Physics89L/blob/main/nb/03_02_More_Error_Propagation.ipynb)
---->
+-->
 
-<!---
+<!--
 * Notes for Week 4: 
   * Topics: Gaussians and p-values
   * [Background and reference](Week4.md)
   * [Notebook 1: "Let's make a Gaussian"](https://github.com/KIPAC/Physics89L/blob/main/nb/04_01_Lets_Make_A_Gaussian.ipynb)
   * [Notebook 2: "Vela pulsar"](https://github.com/KIPAC/Physics89L/blob/main/nb/04_02_Vela_Pulsar.ipynb)
---->
+-->
 
-<!---
+<!--
 * Notes for Week 5: 
   * Topics: Covariance, correlation, chi-square fitting
   * [Background and reference](Week5.md)
   * [Notebook 1: "Correlations"](https://github.com/KIPAC/Physics89L/blob/main/nb/05_01_Correlations.ipynb)
   * [Notebook 2: "Fitting a line to data"](https://github.com/KIPAC/Physics89L/blob/main/nb/05_02_Fitting_A_Line_to_Data.ipynb)
---->
+-->
 
-<!---
+<!--
 * Notes for Week 6: 
   * Topics: Minimizers and fitting
   * [Background and reference](Week6.md)
   * [Notebook 1: "Optimizing a fit and how to do it wrong"](https://github.com/KIPAC/Physics89L/blob/main/nb/06_01_Optimizing_a_fit_and_how_to_do_it_wrong.ipynb)
   * [Notebook 2: "SDSS Spectra"](https://github.com/KIPAC/Physics89L/blob/main/nb/06_02_SDSS_Spectra.ipynb)
---->
+-->
 
-<!---
+<!--
 * Notes for Week 7: 
   * Topics: Data selection, efficiency, leakage, and rare event searches
   * [Background and reference](Week7.md)
   * [Notebook 1: "Optimizing selections"](https://github.com/KIPAC/Physics89L/blob/main/nb/07_01_Cuts_Acceptance_Leakage.ipynb)
   * [Notebook 2: "Performing a dark matter search"](https://github.com/KIPAC/Physics89L/blob/main/nb/07_02_Performing_a_Dark_Matter_Search.ipynb)
---->
+-->
 
-<!---
+<!--
 * Notes for Week 8: 
   * Topics: Frequency analysis
   * [Background and reference](Week8.md)
   * [Notebook 1: "Introduction to Fourier Analysis"](https://github.com/KIPAC/Physics89L/blob/main/nb/08_01_Intro_Fourier_Analysis.ipynb)
   * [Notebook 2: "Ripples in 2D Electron Gas"](https://github.com/KIPAC/Physics89L/blob/main/nb/08_02_Ripples_in_2D_Electron_Gas.ipynb)
---->
+-->
 
-<!---
+<!--
 * Final Projects:
   * [Overview](Projects.md)
---->
+-->
 
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