100 families with two children were selected randomly and the following data were recorded :
`{:("No. of girls in family",2,1,0),("No. of families",12,80,8):}`
Calculate the probability of a family chosen at random having
One girl.

Answer

To calculate the probability of a family chosen at random having one girl, we can follow these steps:

### Step 1: Understand the Data
We have data for 100 families with two children. The number of girls in the families and the corresponding number of families are as follows:
- Families with 2 girls: 12
- Families with 1 girl: 80
- Families with 0 girls: 8

### Step 2: Identify Total Families
The total number of families surveyed is given as:
\[ \text{Total Families} = 100 \]

### Step 3: Identify Favorable Outcomes
We need to find the number of families that have exactly one girl. From the data, we see that:
\[ \text{Number of families with 1 girl} = 80 \]

### Step 4: Calculate the Probability
The probability \( P \) of a family having one girl can be calculated using the formula:
\[ P(\text{One girl}) = \frac{\text{Number of families with one girl}}{\text{Total number of families}} \]
Substituting the values we have:
\[ P(\text{One girl}) = \frac{80}{100} \]

### Step 5: Simplify the Probability
Now, we can simplify the fraction:
\[ P(\text{One girl}) = \frac{80}{100} = \frac{4}{5} \]

### Step 6: Convert to Decimal Form
To express this probability in decimal form:
\[ P(\text{One girl}) = 0.8 \]

### Final Answer
Thus, the probability of a family chosen at random having one girl is:
\[ \frac{4}{5} \text{ or } 0.8 \]

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