Marks of `10` students in an English test are as follow, `9,10,7,11,12,6,8,14,15,18`. Find mean marks

Options

A. `15`
B. `12`
C. `11`
D. `18`

Answer

To find the mean marks of the 10 students in the English test, we will follow these steps:

### Step 1: List the Marks
The marks of the 10 students are:
- 9
- 10
- 7
- 11
- 12
- 6
- 8
- 14
- 15
- 18

### Step 2: Sum the Marks
We need to add all the marks together:
\[ 9 + 10 + 7 + 11 + 12 + 6 + 8 + 14 + 15 + 18 \]

Calculating the sum step-by-step:
- \( 9 + 10 = 19 \)
- \( 19 + 7 = 26 \)
- \( 26 + 11 = 37 \)
- \( 37 + 12 = 49 \)
- \( 49 + 6 = 55 \)
- \( 55 + 8 = 63 \)
- \( 63 + 14 = 77 \)
- \( 77 + 15 = 92 \)
- \( 92 + 18 = 110 \)

So, the total sum of the marks is \( 110 \).

### Step 3: Count the Total Number of Observations
The total number of observations (students) is \( 10 \).

### Step 4: Calculate the Mean
Using the formula for mean:
\[ \text{Mean} = \frac{\text{Sum of all observations}}{\text{Total number of observations}} \]
Substituting the values we have:
\[ \text{Mean} = \frac{110}{10} \]

Calculating this gives:
\[ \text{Mean} = 11 \]

### Final Answer
The mean marks of the students is \( 11 \).

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