#### Answer

The weighted mean is 64.5

#### Work Step by Step

The weighted mean is the average of all the numbers in a set of numbers. If a number occurs multiple times it is counted that many times in the average.
Sum the frequencies to find the total number of items in the set.
$f=4+10+8+12+10=44$
Sum all the test scores and divide by the frequency count to find the weighted mean.
$m=((46\times4)+(54\times10)+(62\times8)+(70\times12)+(78\times10))\div44$
=$(184+540+496+840+780)\div44$
=$2840\div44$
=$64.5$