Anti-Markownikoff rule applies to addition reactions in presence of HBr. It states that negative part of reagent adds to the carbon atom having more number of hydrogen atoms.
We will apply this rule to find the product.
$\underset{\text{Isobutene}}{CH _{3}- \underset{\overset{|}{C}H_3}{C} = CH _{2}}+ HBr \xrightarrow{\text { Peroxide }} \underset{\text{Isobutyl bromode}}{ CH _{3}- \underset{\overset{|}{C}H_3}{CH} - CH _{2} Br}$