I have the following table Jan:32 Feb.19 Mar.30 April.52 May.80 June.54 July.27 Aug.

( I thought was 0.82796)

I thought I knew how to find the unusual values but my teacher said

"When finding the unusual values, remember to multiply the standard deviation by 2" So how do I find them.

I also want to use this information to explore the normal distribution.

assuming my bills are known to have a normal distribution. what is the probability that my next bill we be less than $150? I do not know how to find this. Can you help me understand????