The accompanying data on $x=$ head circumference $z$ score $($a comparison score with peers of the same age $-$ a positive score suggests a larger size than for peers$)$ at age $6$ to $14$ months and $y=$ volume of cerebral grey matter $($in ml$)$ at age $2$ to $5$ years were read from a graph in an article.

$\backslash$table$[[\backslash$table$[[$Cerebral Grey$],[$Matter $($ml$)2-5$ yr$]],\backslash$table$[[$Head Circumfer$-],[$ence $z$ Scores at$],[6-14$ Months$]]],[680,-0\mathrm{.}71],[690,1\mathrm{.}6],[700,-0\mathrm{.}26],[720,0\mathrm{.}29],[740,0\mathrm{.}34],[740,1\mathrm{.}9],[750,1\mathrm{.}5],[750,2\mathrm{.}4],[760,1\mathrm{.}5],[780,1\mathrm{.}5],[790,2\mathrm{.}4],[810,2\mathrm{.}5],[815,3\mathrm{.}2],[820,2\mathrm{.}6],[825,0\mathrm{.}94],[835,2\mathrm{.}75],[840,2\mathrm{.}7],[845,2\mathrm{.}6]]$

$($a$)$ What is the value of the correlation coefficient? $($Give the answer to two decimal places.$)r=$

$($b$)$ Find the equation of the least$-$squares line. $($Give the answer to two decimal places.$)$

hat$(y)=$

$($c$)$ Predict the volume of cerebral grey matter for a child whose head circumference $z$ score at age $12$ months was $1\mathrm{.}7.($Give the answer to two decimal places.$)$