Answer:
- The missing frequency for class 2 ≤ t < 4 is 18.
- The median class is 4 ≤ t < 6.
- The modal class is 4 ≤ t < 6.
Step-by-step explanation:
We can complete the frequency table by calculating the total frequency and the given frequencies.
The total frequency equals to the total of teenagers and it is divided into the classes. Let the frequency of class 2 ≤ t < 4 = x, then:
[tex]14 + x + 37 + 18 + 13 = 100[/tex]
[tex]\bf x=18[/tex]
For the median class, we can use the cumulative frequency:
[tex]\begin{array}{c|c|c} time/hour & frequency & cumulative\ freq\\\cline{1-3} 0\leq t < 2 &14 & 14\\\cline{1-3} 2\leq t < 4 &18 & 14+18=32\\\cline{1-3} 4\leq t < 6 &37 & 32+37=69\\\cline{1-3} 6\leq t < 8 &18 & 69+18=87\\\cline{1-3} 8\leq t < 10 &13 & 87+13=100 \end{array}[/tex]
Since the total frequency = 100, then the median should be the mean of 50th and 51th data, which falls in the class 4 ≤ t < 6 (it contains the 33th up to 69th data).
For the modal class, we only look for the class with the highest frequency which is class 4 ≤ t < 6.
