The Number of Houses Sold in a Suburb in Sydney

Essay

The number of houses sold in a suburb in Sydney and the average monthly mortgage rates for 18 months randomly selected are shown in the following table. $$\begin{array} { | c | c | c | c | } \hline \begin{array} { c } \text { Mortgage } \\\text { rate (\%) }\end{array} & \begin{array} { c } \text { Number of } \\\text { houses sold }\end{array} & \begin{array} { c } \text { Mortgage } \\\text { rate (\%) }\end{array} & \begin{array} { c } \text { Number of } \\\text { houses sold }\end{array} \\\hline 7.5 & 90 & 9.5 & 68 \\\hline 9.0 & 72 & 6.5 & 97 \\\hline 7.0 & 89 & 8.0 & 79 \\\hline 10.5 & 62 & 9.0 & 75 \\\hline 10.0 & 58 & 10.5 & 53 \\\hline 9.5 & 70 & 9.5 & 73 \\\hline 8.5 & 74 & 11.0 & 50 \\\hline 10.0 & 65 & 7.5 & 82 \\\hline 11.0 & 51 & 8.5 & 70 \\\hline\end{array}$$ a. Draw a scatter diagram with the number of houses sold on the vertical axis.
b. Describe the relationship between mortgage rate and number of houses sold.