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
I want more points next time....Hehehee!
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<em>Solution in attachments!</em>
The correct answer would be: C. 44
Explanation: If you're trying to find out x's value, you have to do the inverse operation which means if it's subtraction, you add. So to find x's value, you'd add 36 + 8 = x. And 36 + 8 = 44. So therefore, x = 44. That means the answer is C.
SOLUTION:
Case: Percentages
Method:
The sale price after 30% off is $6800
Let the original price be 'x'
30% off means 70% of the original price
Final answer: (Nearest cents)
The original price was $9714.29
Answer:
39.5
Step-by-step explanation:
angle ABC=60=(5x+2)+(3x-2)
60=8x
x=7.5
Angle ABD=(5x+2),(sub x=7.5)
=(5*7.5+2)
=39.5
