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:
437.4 meters squared
Step-by-step explanation:
7.2*4.5=32.4=b
3*4.5=13.5=h
b*h=a
32.4*13.5=437.4m^2
Answer:
it is 29in
Step-by-step explanation:
Y
=
−
2
x
+
5
y
=
-
2
x
+
5
Use the slope-intercept form to find the slope and y-intercept.
Tap for more steps...
Slope:
−
2
-
2
y-intercept:
(
0
,
5
)
(
0
,
5
)
Any line can be graphed using two points. Select two
x
x
values, and plug them into the equation to find the corresponding
y
y
values.
Tap for more steps...
x
y
0
5
5
2
0
2(6y - 5) - 3y = 2
12y - 10 - 3y = 2
9y - 10 = 2
9y = 12
y = 4/3, or 1 1/3
2x - 3(4/3) = 2
2x - 12/3 = 2
2x - 4 = 2
2x = 6
x = 3
