Answer:
a) 20<h≤30.
b) 26.17 hrs
Step-by-step explanation:
The missing table is shown in attachment.
Part a)
We need to find the class interval that contains the median.
The total frequency is
[tex] \sum \: f = 30[/tex]
The median class corresponds to half
[tex] \frac{1}{2} \sum \: f ^{th} - - - value[/tex]
That is the 15th value.
We start adding the frequency from the top obtain the least cumulative frequency greater or equal to 15.
2+8+9=19
This corresponds to the class interval 20<h≤30.
Adding from the bottom also gives the same result.
Therefore the median class is 20<h≤30.
b) Since this is a grouped data we use the midpoint to represent the class.
The median is given by :
[tex] \frac{\sum \: fx}{ \sum\: f} [/tex]
[tex] = \frac{5 \times 3 + 15\times 8 + 25 \times 9 + 35 \times 7 + 45 \times 4}{30} [/tex]
[tex] = \frac{785}{30} [/tex]
[tex] = 26.17[/tex]
