(Solved): please fill out chart as well. explanation on chart is appreciated  3) A developmental psycholo ...

3) A developmental psychologist evaluates a large number of infants and toddlers identifying the age at which the children are first able to use 50 words or more. The chart below shows the age at which the child uses 50 words along with the number of children in the sample that are that age when they attain 50 words. Age (in months) 18 19 20 21 22 23 24 Frequency fi 5 10 22 25 15 12 8 Find mean, mode, median, variance and standard deviation.