An article suggests the lognormal distribution as a model for SO2 concentration ...

  

An article suggests the lognormal distribution as a model for SO2 concentration above a certain forest. Suppose the parameter values are μ = 1.9 and σ = 1.2.

(a) What are the mean value and standard deviation of concentration? (Round your answers to three decimal places.

mean: __________      
standard deviation: _____________  

(b) What is the probability that concentration is at most 10? Between 5 and 10? (Round your answers to four decimal places.)

at most 10: ___________
between 5 and 10: _____________