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OpenStax, Statistics §12.5 Outliers · Exercise 17 · Statistics · Regression & correlation

Outliers · Exercise 17

The cost of a leading liquid laundry detergent in different sizes is given in.
\begin{array}{|c|c|c|}\hline \text{Size (ounces)} & \text{Cost ($)} & \text{Cost per Ounce} \\ \hline \text{16} & \text{3.99} & \\ \hline \text{32} & \text{4.99} & \\ \hline \text{64} & \text{5.99} & \\ \hline \text{200} & \text{10.99} & \\ \hline\end{array}

(a) Using size as the independent variable and cost as the dependent variable, draw a scatter plot.
(b) Does it appear from inspection that there is a relationship between the variables? Why or why not?
(c) Calculate the least-squares line. Put the equation in the form ŷ = a + bx.
(d) Find the correlation coefficient. Is it significant?
(e) If the laundry detergent were sold in a 40 oz. size, what is the estimated cost?
(f) If the laundry detergent were sold in a 90 oz. size, what is the estimated cost?
(g) Does it appear that a line is the best way to fit the data? Why or why not?
(h) Are there any outliers in the given data?
(i) Is the least-squares line valid for predicting what a 300 oz. size of the laundry detergent would cost? Why or why not?
(j) What is the slope of the least-squares (best-fit) line? Interpret the slope.

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OpenStax, Statistics · §12.5 Outliers · Exercise 17

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