A company that produces $8$ pound bags of potting mix and gathered $3$ samples of $5$ bags. The weights of each bag are listed below. What is $?$

Sample

$1$

$2$

$3$

$4$

$5$

$1$

$7\mathrm{.}98$

$8\mathrm{.}34$

$8\mathrm{.}02$

$7\mathrm{.}94$

$8\mathrm{.}44$

$2$

$8\mathrm{.}33$

$8\mathrm{.}22$

$8\mathrm{.}08$

$8\mathrm{.}51$

$8\mathrm{.}41$

$3$

$8\mathrm{.}24$

$8\mathrm{.}18$

$7\mathrm{.}83$

$8\mathrm{.}05$

$7\mathrm{.}9$

a$.0\mathrm{.}49$

b$.0\mathrm{.}56$

c$.0\mathrm{.}45$

d$.0\mathrm{.}52$