Nope, the answer is three. Mean means the average of all the numbers. So all you have to do is to add the numbers up and divide the the amount of numbers with your sum.
Answer:
82.62
Step-by-step explanation:
Mean score (μ) = 80
Standard deviation (σ) = 5
The 70th percentile of a normal distribution has an equivalent z-score of roughly 0.525.
For any given score, X, the z-score can be determined by:

For z = 0.525:

A raw score of approximately 82.62 corresponds to the 70th percentile.
Answer: Mr. Lee’s entire face crinkles and lights up when he smiles.
Step-by-step explanation:
X+23=-22
-23 -23
x=-45
a+(-1.3)=-4.5
or
a-1.3+-4.5
+1.3 +1.3
a=3.2
3y+4y+6=20
(3y+4y)+(6)=20
(Combine Like Terms)
7y+6=20
7y+6=20
Subtract 6 from both sides.
7y + 6 − 6 = 20 − 6
7y = 14
Divide both sides by 7.
7y/7 = 14/7
y = 2