For a standard normal distribution, determine the probability of ...

[codyclark]

For a standard normal distribution, determine the probability of obtaining a Z value of
 a. greater than zero.
  b. between -2.34 to -2.55
  c. less than 1.86.
  d. between -1.95 to 2.7.
  e. between 1.5 to 2.75.

Question 2

The time it takes a worker on an assembly line to complete a task is exponentially distributed with a mean of 8 minutes.
 a. What is the probability density function for the time it takes to complete the task?
  b. What is the probability that it will take a worker less than 4 minutes to complete the task?
  c. What is the probability that it will take a worker between 6 and 10 minutes to complete the task?

[shailee]

Answer to Question 1

a. 0.5000
b. 0.0042
c. 0.9686
d. 0.9709
e. 0.0638

Answer to Question 2

a. f(x) =(1/8 ) e-x/8 for x > 0
b. 0.3935
c. 0.1859