Roll (1984) spread 
////////////////////////////////

Roll (1984) designs a method to estimate the spreads by using the 
    first order covariance of price changes. 

       S=2 *sqrt(-cov(A, B) )                         (1)

          where A= deltaP(t-1)
                B= deltaPP(t)	

 For more detail, see the term project or chapter 30

///////////////////////////////

Amihud's (2002) illiquidity 
////////////////////////////////
Amihud (2002) illiquidity measure uses the absolute daily return over 
   its corresponding trading dollar volume. A monthly stock illiquidity 
   measure is the mean of daily illiquidity measure.  
                   1                |Ri|
       illiq(t)=  --- * sum (--------------- )      (1)
                   n             pi * Vi

   where illiq(t) is a monthly illiquidity measure, n is the number of 
         trading days within the month, Ri is daily return on day i, 
         Vi is the trading volume on day i and Pi is the closing 
         price of the underlying stock on day i. 

  For more detail, see Term Projects

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If "Developer" is not available on your menu bar
/////////////////////////
Windows users
--------------
  Step 1: click 'File' 
  Step 2: click 'Options' 
  Step 3: click 'Customize Ribbon' 
  Step 4: Activate 'developer' and click 'OK'

Mac users
-------------------------
    Select Excel > Preferences > Ribbon & Toolbar.
    Under Customize the Ribbon, select Main Tabs and then check Developer.
    Click Save and then close Excel Preferences.

    http://datayyy.com/webs/developerMac.html

  Video: Enable Developer Tab In Excel 2016 for Mac
         (53second)
          https://www.youtube.com/watch?v=KZ4xTecAxZ4
    
/////////////////////////

Record the simplest Macro
/////////////////////////
 Step 1: Click "Developer"

 Step 2: click "Record Macros"

 Step 3: Macro1  [or another name]
         shortCut Key  + [a]

 Step 4: choose cell B2, type 1 then enter

 Step 5: Click "Stop Recording"

  Now delete the value in B2 and hit Ctrl-a to see the result. 
/////////////////////////