Find the (two) z-scores that bound the middle 40% of the standard normal distribution.
To find the two z scores you would split the 40% into .20 and .20. The z scores would be z = (-.53) and z =( .53)
Instructor says answer was incorrect. Below is her reply.
The middle 40% is found by adding .500 and .2000 to get an area. This is the upper limit of area and we would then proceed to find z when area is known for this one. For the second one we could take .5000 - .2000 =? then find the z for that area. We could also notice that the scores are the same except that the signs are negative (apply the property of symmetry).
You need to apply the same property (symmetry) to Q1 to answer it.
Please clarify.