For a standard normal distribution, find: P(z > 2.14)

Answer 1

Hi Salma,

Remember that a standard normal distribution has mean 0 and standard deviation 1, so we don't even need to do any initial calculation. Just go right to the z-table and look up 2.14. Recall that z-tables provide probabilities that z is less than any given value. For this problem:

P(Z<2.14)=0.9838

Now, when you have less than, but need greater, you can apply the Complement Rule, or as I tend to call it, the One Minus Trick:

P(Z>x)=1-P(Z<x); x=any value you are given for z

So, here:

P(Z>2.14)=1-P(Z<2.14)=

1-0.9838=

P(Z>2.14)= 0.0162

I hope this helps.