In sum you were asked to prepare a frequency distribution table, regarding the concentration of sulphur dioxide in the air in parts per million of a certain city for 30 days. Using this table, find the probability of the concentration of sulphur dioxide in the interval 0.12 -0.16 on any of these days.

Answer

To solve the problem step by step, we will follow the process of calculating the probability of the concentration of sulfur dioxide in the specified interval.

### Step 1: Understand the Problem
We need to find the probability of the concentration of sulfur dioxide in the air being in the interval of 0.12 to 0.16 parts per million over a period of 30 days.

### Step 2: Gather the Given Data
- Total number of days = 30
- Number of days with concentration in the interval 0.12 to 0.16 = 2

### Step 3: Calculate the Probability
The probability (P) of an event is calculated using the formula:

\[ P = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} \]

In this case:
- Number of favorable outcomes (days with concentration in the interval 0.12 to 0.16) = 2
- Total number of outcomes (total days) = 30

So, we can substitute these values into the formula:

\[ P = \frac{2}{30} \]

### Step 4: Simplify the Probability
Now, we simplify the fraction:

\[ P = \frac{2}{30} = \frac{1}{15} \]

### Step 5: Conclusion
The probability of the concentration of sulfur dioxide being in the interval of 0.12 to 0.16 parts per million on any of these days is:

\[ \frac{1}{15} \]

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