$9\mathrm{.}22.$ According to data released by the World Bank, the mean PM$10$

$($particulate matter$)$ concentration for the city of Kabul, Afghani$-$

stan, in $1999$ was $46.$ Suppose that because of efforts to improve air

quality in Kabul, increases in modernization, and efforts to estab$-$

lish environmentally friendly businesses, city leaders believe rates of

particulate matter in Kabul have decreased. To test this notion, they

randomly sample $12$ readings over a one$-$year period, with the result$-$

ing readings shown below. Do these data present enough evidence to