All our answers lie in the above statement.
Confidence Level:
The creator claims that 9 out 10 students will have the average score in the said range. Or in other words we can say that the creator is 90% confident about the result of the field test. So the confidence level is 90%.
Margin of Error:
The average score lies within 4% of 70%. This means the margin of error is 4% i.e. the average scores can deviate from 70% by 4% .
Confidence Interval:
Lower Limit = 70% - 4% = 66%
Upper Limit = 70% + 4% = 74%
Interpretation:
The exam creator is 90% confident that the average scores of seniors will be between 66% and 74%.
We want to simplify √(-48).
Note that
i² = -1 by definition.
Therefore

Answer: c.
20+64=84 40+44=84 74+10=84 30+54=84
The answer is
8/4
7/5
4/3
7/10