Chapter 5, Ex 25

25 Let X be a random variable normally distributed with parameters ยต = 70 sd = 10.

Estimate:

  1. P(X > 50).
pnorm(50, mean=70, sd=10, lower.tail = FALSE)
## [1] 0.9772499
  1. P(X < 60).
pnorm(60, mean=70, sd=10, lower.tail = TRUE)
## [1] 0.1586553
  1. P(X > 90).
pnorm(90, mean=70, sd=10, lower.tail = FALSE)
## [1] 0.02275013
  1. P(60 < X < 80).
pnorm(80, mean=70, sd=10, lower.tail = TRUE) - pnorm(60, mean=70, sd=10, lower.tail = TRUE)
## [1] 0.6826895