Answer:
<em>0.615</em>
Step-by-step explanation:
The frequency table is attached below.
We have to calculate, the probability that the student preferred morning classes given he or she is a junior.
i.e 
We know that,

So,

Putting the values from the table,

Answer is From all those aforementioned, the true statement is: Thanh’s grade is 2.5 standard deviations below the mean of the test grades.
explanation
The z scores are standard deviations. If, for example, a tool returns a z score of +2.5, it means that the result is a standard deviation of 2.5. Very high or very low (negative) z scores associated
with very low p values are at the ends of the normal distribution.
5x5 - 10x = 0
5x5 - 10x = 5x • (x4 - 2)