If strep bacteria causes the infection, it can remain contagious for up to 2 weeks without treatment. However, antibiotics can shorten the contagious period and li â¦ mits to about 24 to 48 hours once the therapy starts.     http://health.top54u.com/post/How-Long-is-Tonsillitis-Contagious.aspx.
Calculate Options Implied Volatility in Excel. Implied Volatility Function: Returns the annualized volatility of an underlying security implied by the market price of a European call or put option on that security, based on Black-Scholes valuation. Description of parameters.
In addition, thereâs actually a volatility surface, or different values of implieds for different strike prices and maturities. Thatâs a topic for another day; today letâs just look at how to calculate a simple historical volatility in Excel. 1. Collect your raw data, in the form of a closing price for each time period. Many people do not know, but Yahoo Finance is a good source of daily data that can be downloaded into a spreadsheet.