Solution: We are given:

Using the empirical rule, we have:
covers 68% of data.
Also the percentage of values below mean = Percentage of values above mean = 50%
Now, let's find the z score for x=20

Therefore, the percentage of values greater than 1 standard deviation above mean 
Expected number of students = 16% of 100 = 16
Between 2 and 3, should be somewhere before .5
Answer:
Option A is correct.
The value of r = -0.7 represents the strongest negative correlation.
Step-by-step explanation:
A correlation is a value that describes a relationship between two things or variables.
Strongest Negative Correlation says that closer a negative correlation to -1, the stronger the relationship between the two variables.
From the options, we have only two negative values i.e, r= -0.7 and r= -0.22.
We have to find the strongest negative correlation r-value.
By the definition, you can see that -0.7 is very closer to -1 ,
therefore, the value of r = -0.7 represents the strongest negative correlation.