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
<span>
Using Pythagoras' theorem it is 6 times the sq rt of 5 which is about 13.416
</span><span>feet to 3 decimal places </span>
x=8.9 because when you square it and divide you get 39.6.. rounded to 40.
You have 2.50.
3 times 10 is 30, so now you have
2.20.
he bought twice as many six cent stamps as ten cent stamps.
multiples of six that are applicable are 30, 60, 90, 120.
six goes into 30 five times. Five can't be divided in half.
six goes into 60 ten times. ten divided in half is five. fifty plus sixty, is only 110.
six goes into ninety 15 times. fifteen can not be divided in half.
six goes into 120 twenty times. 20 divided in half is ten. ten times ten is 100.
100 + 120 = 220.
He bought 10 10cent stamps
