# Question: 1 322 the proportion of observations from a standard normal...

###### Question details

1. (3.22) The proportion of observations from a standard Normal distribution that take values greater than 1.661.66 is about (±±0.001)

2. (3.22) The proportion of observations from a standard Normal distribution that take values less than -1.31 is about (±±0.0001)

3. (3.29) **(a)** Use your calculator to find the
number zz such that the proportion of observations that are less
than zz in a standard Normal distribution is 0.30.3. zz (±±0.01)
=

**(b)** Find the number zz such that 39 % of all
observations from a standard Normal distribution are greater than
zz. zz (±±0.01) =

4. (3.33) Automated manufacturing operations are quite precise but still vary, often with distributions that are close to Normal. The width in inches of slots cut by a milling machine follows approximately the N(0.8750,0.0013)N(0.8750,0.0013) distribution. The specifications allow slot widths between 0.8725 and 0.8775 inch.

What proportion (±±0.001) of slots meet these specifications (use software)?