Griffiths Quantum Mechanics Problem 1.2: Standard Deviation of Probability Distribution

Problem from Introduction to Quantum Mechanics, 2nd edition, by David J. Griffiths, Pearson Education, Inc.

[@01rai01]

Title needs correcting,
I came here for Problem 1.11, ended up doing 1.2 instead (still worth it).

[@password6975]

Thanks man

[@ifrazali3052]

Thanks