1. For some population the values of the measurement of interest have mean 
   mu=0 and standard deviation sigma=1. Assume that these values are 
   normally distributed. Complete the following:
   a) Determine the proportion of values greater than 3.00. 
   b) Determine the proportion of values less than -2.53. 
   c) Determine the proportion of values greater than -0.76.

2. Assume that the wait time (ms) of database transactions, for some DBMS,
   is normally distributed with mean mu=60.0ms and standard deviation 
   sigma=10.0ms.
   a) Find the proportion of transactions that waited for between 36.0ms
      and 48.0ms. 
   b) Find the proportion of transactions that waited for less than
      15.2ms. 
   c) Consider the wait time 41.5ms. Determine the percentile rank for
      this wait time.
   d) Determine the wait time that defines the 55th percentile. 
   e) Determine the wait time that defines the 25th percentile.