Case $$1$$: frequency $$10-19,$$ The lower class limit is $$10$$ The upper class limit is $$20$$ Mid-value is, $$dfrac{10+19}{2}=14.5$$ Case $$2$$: frequency $$20-29,$$ The lower class limit is $$20$$ The upper class limit is $$29$$ Mid-value is, $$dfrac{20+29}{2}=24.5$$ Case $$3$$: frequency $$30-39,$$ The lower class limit is $$30$$ The upper class limit is $$39$$ Mid-value is, $$dfrac{30+39}{2}=34.5$$ Case $$4$$: frequency $$40-49,$$ The lower class limit is $$40$$ The upper class limit is $$49$$ Mid-value is, $$dfrac{40+49}{2}=44.5$$