Question

For a standard normal distribution, find:

P(z > -0.86)

P(z > c) = 0.3338. Find C.

P(z > -0.86)

Answer 1

Explanation:

Given that a variable follows a standard normal distribution

Z is N(0,1)

Thus we can use the standard normal distribution table to find the required probabilities or c

a)
`P(z > -0.86)`

We know std normal is symmetric about 0. Hence this prob is area from 0 to end on right side and 0 to 0.86 on left side

= sum of two prob = 0.3051+0.5=0.8051

b)
`P(z > c) = 0.3338`

Since prob is less than 0.5 we find that c lies to the right of 0. i.e.c is positive

Between 0 and c prob
`= 0.5-0.3338 = 0.1662`

Seeing the table we find that c = 0.43