Question

To find out the concentration of SO₂

in the air (in parts per million, i.e., ppm), the data was collected for 30 localities in a certain city and is presented below:
Concentration of SO₂(in pmm) Frequency
0.00−0.04 4
0.04−0.08 9
0.08−0.12 9
0.12−0.16 2
0.16−0.20 4
0.20−0.24 2
Find the mean concentration of SO₂ in the air

Answer 1

The mean concentration of SO₂ in the air is 0.083 ppm.

Step-by-step explanation:

To find the mean concentration of SO₂ in the air, we need to calculate the weighted average. This can be done by multiplying each concentration by its corresponding frequency, summing the products, and dividing by the total frequency. Let's perform the calculations:

• Concentration of 0.00−0.04 ppm with a frequency of 4: 0.02 ppm
• Concentration of 0.04−0.08 ppm with a frequency of 9: 0.36 ppm
• Concentration of 0.08−0.12 ppm with a frequency of 9: 0.72 ppm
• Concentration of 0.12−0.16 ppm with a frequency of 2: 0.28 ppm
• Concentration of 0.16−0.20 ppm with a frequency of 4: 0.64 ppm
• Concentration of 0.20−0.24 ppm with a frequency of 2: 0.48 ppm

Summing up all the concentrations gives us a total of 2.50 ppm. The total frequency is 30. Therefore, the mean concentration of SO₂ in the air is 2.50 ppm / 30 = 0.083 ppm.