Query in understanding upper confidence limit Q11 of IFoA April 2011 (iii)

Please ref. to Q11 of IFoA April 2011 (iii) part. I think this "2.3263" is coming from normal table. Can anyone kindly help me to understand why they are taking e^(mu+sigma*2.3263)? Is it because of log-normal and they have asked us to find the upper limit? In case they had asked us to find the lower limit, we had to do e^(mu-sigma*2.3263) right??? Please help me to understand this.

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1)yes its coming from normal table.
2)As u see in i)dev factors(df) follows log normal,log(df)~N(meu,sigma).So mean of log(df) is e^(mu+sigma*2.323)
3)yes,for lower limit we use minus.

 

Varsha, thank you so much! Can you please help me with the other query I posted yesterday? I am confused to see that for both "incurred claims" and "paid claims" they are sometimes using same solution techniques - why?