7x +7y + 7 hope this helps as an expansion :)
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:
118
Step-by-step explanation:
To find the height of the TV you first need to realize that the question is giving you dimensions for a triangle.
Every triangle has a hypotenuse and two sides. To find the hypotenuse you square both sides, add them, and then square root. So to find one of the sides you get the hypotenuse, square it, and subtract the square length of the given side.
The equation is 25^2-20^2.
Which if simplified is 625-400, the then solution is going to be 225.
You next will square root 225, 225^(1/2). Which your answer should be 15 inches for the missing side length.
Answer:
x = 27
Step-by-step explanation:
The angle at any point on a straight line is 180 degrees.
The middle line over there is creating a right angle which is 90 degrees.
This must mean that both sides are 90 degrees.
3x+9 = 90
3x = 81
x = 27
