Mean is
and a standard deviation is
, then the variable
.
Use substitution
.
This substitution gives you that
.
a. For X=130,
and
(the decimal value is taken from the Standard Normal Distribution Table).
b. For X=90,
and for X=110,
. Then
(the decimal value is taken from the Standard Normal Distribution Table).
Explanation:
<u><em>First you subtract by -1 both sides of an equation.</em></u>
<u><em>
</em></u>
<u><em>Then, simplify the number.</em></u>
<u><em>34-1=33</em></u>
<u><em>x>33</em></u>
<u><em>Or interval notation 33,∞ </em></u>
<u><em>Final answer: → x>33 and 33,∞</em></u>
<u><em>Hope this helps!</em></u>
<u><em>Thanks!</em></u>
Answer: Phone C
Using quick mental math, we can do 8% of 10 to get 0.8, which is close to the value of 0.0845*10. Also fairly quick is moving the decimal point over 1 spot to the right and we go from 0.0845 to 0.845 and that rounds to 0.8 when rounding to one decimal place. Recall that 8.45% = (8.45/100) = 0.0845
If you want to compute out the four results with a calculator, then it would look like this:
0.0845*20 = 1.69
0.0845*25 = 2.1125
0.0845*10 = 0.845
0.0845*18 = 1.521
and this shows that no other result (but choice C) is close to 0.8
So that's why the answer is choice C