PROBABILITY & STATISTICS
EXAM N5 – FULLY SOLVED
First-Year University Level
Includes:
* Step-by-step solutions
* Clear formulas and explanations
* Practical exercises with interpretation
, Exercise 1 – Frequency Table and Mean
Problem
The following table shows the number of absences of students
during a semester.
Absences (xᵢ):
0|1|2|3|4
Frequency (fᵢ):
3|5|6|4|2
a) Calculate the total number of students
b) Calculate the mean number of absences
Solution
Total students:
n = 3 + 5 + 6 + 4 + 2 = 20
Mean formula:
x̄ = Σ(xᵢ · fᵢ) / n
Σ(xᵢ · fᵢ) = (0·3) + (1·5) + (2·6) + (3·4) + (4·2)
Σ(xᵢ · fᵢ) = 0 + 5 + 12 + 12 + 8 = 37
Mean:
x̄ = = 1.85
Result:
Mean number of absences = 1.85
EXAM N5 – FULLY SOLVED
First-Year University Level
Includes:
* Step-by-step solutions
* Clear formulas and explanations
* Practical exercises with interpretation
, Exercise 1 – Frequency Table and Mean
Problem
The following table shows the number of absences of students
during a semester.
Absences (xᵢ):
0|1|2|3|4
Frequency (fᵢ):
3|5|6|4|2
a) Calculate the total number of students
b) Calculate the mean number of absences
Solution
Total students:
n = 3 + 5 + 6 + 4 + 2 = 20
Mean formula:
x̄ = Σ(xᵢ · fᵢ) / n
Σ(xᵢ · fᵢ) = (0·3) + (1·5) + (2·6) + (3·4) + (4·2)
Σ(xᵢ · fᵢ) = 0 + 5 + 12 + 12 + 8 = 37
Mean:
x̄ = = 1.85
Result:
Mean number of absences = 1.85
