Uses the standard normal distribution qnorm

Statistics 302	Spring 2014	Larget	Assignment #6	posted March 3, 2014

Due Friday, March 14

1 - pnorm(650, mean = 500, sd = 100)

## [1] 0.06681

## [1] 1.282

qnorm(0.9, mean = 500, sd = 100)

2. P (X > 260).

3. P (|X − 250| > 40).

8. The number c so that P (X − 250| < c) = 0.9.

R problem 2 The height of the density function of a normal curve can be computed with the R function dnorm(). Write a function called anorm() that will draw a sketch of a normal density and shade in the two tails with probability α/2 if one passes in a mean, sd, and alpha value. Modify this function which calculates and draws P (X ≤ a).