Answer:
a) The class interval containing the median is the interval 2 ≤ h < 3
b) The mean number of hours the children spent on their tablets is 2.2 hours.
Step-by-step explanation:
a) The given parameters are;
The number of students that spent 0 ≤ h < 1 hour = 4
The number of students that spent 1 ≤ h < 2 hours = 8
The number of students that spent 2 ≤ h < 3 hours = 11
The number of students that spent 3 ≤ h < 4 hours = 7
The median is given by the location of the 15th child which is located in the interval given as follows;
We note that the total number of children is obtained by adding the frequencies of the intervals together, as follows;
The number of children = 4 + 8 + 11 + 7 = 30
The frequency of the first interval = 4
The sum of the first + Second intervals = 4 + 8 = 12
The sum of the first + Second + Third intervals = 4 + 8 + 11 = 23
Therefore, the class interval containing the median is the interval 2 ≤ h < 3
b) We use the midpoint of each class interval to find the mean as follows;
The mean = ∑fh/∑h
∴ The mean = (4 × 0.5 + 8 × 1.5 + 11 × 2.5 + 7 × 3.5)/(4 + 8 + 11 + 7) = 2.2
The mean number of hours the children spent on their tablets = 2.2 hours.
