statistics , question 5, grade 10
- After a survey done on the ages of 50 children on their first day at a scouts’ camp, the results were shown in the following table:
|n0” of chidren||10||15||20||5||50|
- Calculate the mean
and the standard deviation σ.
- Find the number of children whose ages belong to the set:
- That day, a competition was held and only children whose ages are at least 10 can participate, find the percentage of those who can participate.
- On the second day, a group of 12 years old children joined the camp and the mean age becomes 11, find the number of these children.