Question

Using the Standard Normal Table. What is the probability a z-score is between -1.11 and 0.91?

In other words, what is P( -1.11 < z < 0.91)?

	A.	0.0479
	B.	0.5186
	C.	0.9521
	D.	0.6851

Answer 1

We have to find P( -1.11 < z < 0.91)

P( -1.11 < z < 0.91) = P( z < 0.91 ) - P( z < -1.11 )

Using the Standard Normal Table

Let's find P( z < -1.11 )

Split z = -1.11 such as (-1.1+0.01) , now search -1.1 in first column and 0.01 in first row then look cross value .

..

P( z < -1.11 ) = 0.1335

Now similarly find P( z < 0.91 )

P( z < 0.91 ) = 0.8186

So,

P( -1.11 < z < 0.91) = P( z < 0.91 ) - P( z < -1.11 )

P( -1.11 < z < 0.91) = 0.8186 - 0.1335 = 0.6851

Option D is correct !!