Question

• 7. Unfortunately, Henry was in a motorcycle accident in which he suffered a serious head trauma. Dr. Gatz, a neurological psychologist, is giving Henry several cognitive tests to help determine if specific neurological pathways were damaged by the accident. For the first test, Henry had to listen to lists of words and then repeat them back. Dr. Gatz recorded how many words Henry could hear and then repeat back correctly. The adult population can repeat back an average of 7 words with a standard deviation of 1.30 words (i.e., µ = 7; σ = 1.30). Henry was able to repeat back 6 words. Use a z score to determine the proportion of people in the adult population who scored better than Henry on this memory test. Assume that the population of memory scores on this test is normally distributed.

find z and the proportion

Answer 1

Solution:

We have to find

Using the z-score formula, we have:

Now we have to find the proportion of people in the adult population who scored better than Henry on this memory test. Then we have:

Now using the standard normal table, we have:

Therefore, the proportion of people in the adult population who scored better than Henry on this memory test is 0.7794