Answer: 0.8238
Step-by-step explanation:
Given : Scores on a certain intelligence test for children between ages 13 and 15 years are approximately normally distributed with and .
Let x denotes the scores on a certain intelligence test for children between ages 13 and 15 years.
Then, the proportion of children aged 13 to 15 years old have scores on this test above 92 will be :-
Hence, the proportion of children aged 13 to 15 years old have scores on this test above 92 = 0.8238
So you do 79+89+90=258 then you take 258/3=9.3 so you would get a 93% test average
Hope this helps
4(4) -4 = 16-4 = 12
She was wrong because she thought that x= 6