Answer:
The actual dimensions would be 3.375 feet by 3.5 feet. The area of the room would be 11.8 square feet.
Step-by-step explanation:
Population = 135 students
Mean score = 72.3
Standard deviation of the scores = 6.5
Part (a): Students from 2SD and 3SD above the mean
2SD below and above the mean includes 95% of the population while 3SD includes 99.7% of the population.
95% of population = 0.95*135 ≈ 129 students
99.7% of population = 0.997*135 ≈ 135 students
Therefore, number of students from 2SD to 3SD above and below the bean = 135 - 129 = 6 students.
In this regard, Students between 2SD and 3SD above the mean = 6/2 = 3 students
Part (b): Students who scored between 65.8 and 72.3
The first step is to calculate Z values
That is,
Z = (mean-X)/SD
Z at 65.8 = (72.3-65.8)/6.5 = 1
Z at 72.3 = (72.3-72.3)/6.5 = 0
Second step is to find the percentages at the Z values from Z table.
That is,
Percentage of population at Z(65.8) = 0.8413 = 84.13%
Percentage of population at (Z(72.3) = 0.5 = 50%
Third step is to calculate number of students at each percentage.
That is,
At 84.13%, number of students = 0.8413*135 ≈ 114
At 50%, number of students = 0.5*135 ≈ 68
Therefore, students who scored between 65.8 and 72.3 = 114-68 = 46 students
Answer: option c.
Step-by-step explanation:
You need to remember the identity:
The inverse of the tangent function is arctangent. You need to use this to calculate the angle "R":
You know that you need to find the measure of "R" and 
(which is the opposite side) and 
(which is the adjacent side), you can sustitute values into
Then, you get:
Answer: last option (5π√146 units²)
Step-by-step explanation:
To solve the exercise you must apply the formula for calculate the lateral area of a cone, which is shown below:
where r is the radius but L is the slant height.
As you can see in the figure attached:
But you need to find the slant height with the Pythagorean Theorem (L would be the hypotenuse):
Substitute into the formula, then:
units²
Answer:
Faction of population = 1.39 / 7.2
Percentage of population = 19.3% (Approx.)
Step-by-step explanation:
Given:
China's population in 2014 = 1.39 billion (Approximately)
Find:
Compare China's population to world population
Computation:
World's population in 2014 = 7.2 billion (Approximately)
Faction of population = China's population in 2014 / World's population in 2014
Faction of population = 1.39 / 7.2
Percentage of population = [China's population in 2014 / World's population in 2014]100
Percentage of population = [1.39/7.2]100
Percentage of population = [0.193]100
Percentage of population = 19.3% (Approx.)
