Question

_________% of the scores fall between a z-score of -1.00 and a z-score of +2.00

		17.89
		81.85
		48.32
		65.17

Answer 1

We have to find the percentage of the scores that fall between a z-score of -1.00 and a z-score of +2.00.

So, first we find the probability that a randomly selected score falls between z=-1.00 and z=2.00.

So, we find

Where, phi is the distribution function of the standard normal variate.

From the standard normal table, this becomes

So, the corresponding percentage is 0.8185*100, ie. 81.85%.

So, the correct answer is option (b) 81.85%.