b) The max noise level is 1.5 dB per thousand people
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Explanation:
As the name suggests, we have 2 dimensions to the table. Along the left is one variable, and the top is another variable. This helps us lay out all the possible outcomes in a visual organized way.
There's not much to talk about here. The name pretty much speaks for itself. Each category is basically like a separate bin or name.
Frequency refers to the count of something (eg: 30 people have a hat) while relative frequency is how that count is in relation to the total (eg: 10% of the group has a hat). Relative frequencies can be expressed as fractions, decimal form, or percentage form. It will depend on what your teacher wants.
We consider the variables to be dependent if they are linked somehow. For example, if it rains, then its fairly likely the number of accidents on the road increases. The variables "it rains" and "number of accidents" are dependent and associate with each other.
The value 1.5 is the slope of the regression line. Note how the line is in the form y = mx+b with m = 1.5; the slope tells us the rate of change. Each time x goes up by 1, the predicted y value goes up by 1.5 decibels. In this context, it means that each time you add 1000 people, the predicted/estimated max noise level will increase by 1.5 dB. For context, a whisper is at about 30 dB, regular talking is about 50 dB, while a jet engine is about 140 dB.
