In: Statistics and Probability
A student received the following grades.
C in Math 120 worth 4 credits.
B in English 125 and worth 3 credits
A in Chem 102 and worth 5 credits.
X ( x - µ ) (x - µ )2
2
5
6
(1)
Answer is:
3.083
Explanation:
From the given data, the following Table is calculated:
| Course | Credit | Grade | Grade Point | 
| Math 120 | 4 | C (2 Grade Points) | 4 X 2= 8 | 
| English 125 | 3 | B (3 Grade Points) | 3 X 3 = 9 | 
| Chem 102 | 5 | A (4 Grade Points) | 5 X 4 = 20 | 
| Total | 12 | 9 | 37 | 
Overall Grade Point Average (GPA) = Total Grade Point/Total Credits
= 37/12
= 3.083
(2)
= 35
= 3
(i)
68 % of the data lie between :

(ii)
95% of the data lie between

(iii)
99.7 % of the data lie between

(3)
Answers are:
mean = 4.3333
variance = 2.8889
standard deviation = 1.6997
Explanation:
(i)
= Population Mean = 13/3 = 4.3333
(ii)
| x | (x -  
) | 
(x -  
)2 | 
| 2 | - 2.3333 | 5.4444 | 
| 5 | 0.6667 | 0.4444 | 
| 6 | 1.6667 | 2.7778 | 
| Total = | 8.6667 | 
So,
Population Variance (
)
is given by:

(iii)
Population Standard Deviation (
)
is given by:
