Answer:
a) Percentage of students scored below 300 is 1.79%.
b) Score puts someone in the 90th percentile is 638.
Step-by-step explanation:
Given : Suppose a student's score on a standardize test to be a continuous random variable whose distribution follows the Normal curve.
(a) If the average test score is 510 with a standard deviation of 100 points.
To find : What percentage of students scored below 300 ?
Solution :
Mean
,
Standard deviation 
Sample mean 
Percentage of students scored below 300 is given by,






Percentage of students scored below 300 is 1.79%.
(b) What score puts someone in the 90th percentile?
90th percentile is such that,

Now, 






Score puts someone in the 90th percentile is 638.
Step-by-step explanation:
The domain of the function is the range of x-values, which is -5 <= x <= 5. (D)
The angle between two vectors is given by:
cos (x) = (v1.v2) / (lv1l * lv2l)
We have then:
v1.v2 = (2, -5). (4, -3)
v1.v2 = (2 * 4) + (-5 * (- 3))
v1.v2 = 8 + 15
v1.v2 = 23
We look for the vector module:
lv1l = root ((2) ^ 2 + (-5) ^ 2)
lv1l = 5.385164807
lv2l = root ((4) ^ 2 + (-3) ^ 2)
lv2l = 5
Substituting values:
cos (x) = (23) / ((5.385164807) * (5))
x = acos ((23) / ((5.385164807) * (5)))
x = 31.33 degrees
Answer:
The angle between the two vectors is:
x = 31.33 degrees
Multply across the fraction so
1/2 * 3/4= (1*3)/(2*4)=3\8
7.77777777 repeating
Irrational numbers are:
Numbers that repeat
7.7777777 repeats the number 7 after the decimal
Numbers that CANNOT be written as a simple fraction.
7.7777777 cannot be written as a fraction in simplest form.
Answer = 7.777777777 repeating
~Aamira~
Hope this helped :)