Question

The table shows the time a patient spends at the dentist and the amount of the bill.

Answer 1

Answer-

Correlation coefficient for the data in the table was found to be 0.93.

Solution-

Taking the independent variable or input variable as, the time a patient spends at the dentist and the dependent variable or output variable as the amount of the bill.

We know that,

$r=\frac{n(\sum xy)-\sum x \sum y}{\sqrt{[n\sum x^{2} -({\sum x})^{2}]\times [n\sum y^{2} -({\sum y})^{2}]}}$

Calculating the values from the table, then putting it in the formula

$r=\frac{4 \times 3130.9 \ - \ 6.45 \times 1473}{\sqrt{[4\times 12.3725 \ - \ 6.45^{2}][4 \times 877475 \ - \ 1473^2]}}$

$\Rightarrow r=0.929720561 \approx 0.93$

∴  Correlation coefficient for the data is 0.93.

Answer 2

The answer is D: 0.93
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