1.139 IQR for Normal distributions. Continue your work from the previous exercise. The interquartile range IQR is the distance between the first and third quartiles of a distribution.

1. (a) What is the value of the IQR for the standard Normal distribution?

2. (b) There is a constant c such that IQR − cσ for any Normal distribution N(μ, σ). What is the value of c?