Hi, I have the table filled out but I need help with 1-4. Anybody out there who can help me?

A developmental psychologist is examining the development of language skills from age 2 to age 5. Four different groups of children are obtained, one for each age, with an n=15 children per group. Each child is given a language skills assessment test. The resulting data were analyzed with an ANOVA to test for mean differences between age groups. The results of the ANOVA are presented in the following table. Fill in the missing values and test for significance