Final answer:
The class width of the 15 < t < 23 class is 8. The frequency density of the 15 < t < 23 class is 0.1375.
Step-by-step explanation:
The class width of the 15 < t < 23 class can be calculated by subtracting the lower class boundary from the upper class boundary. In this case, the lower class boundary is 15 and the upper class boundary is 23. Therefore, the class width is 23 - 15 = 8.
To calculate the frequency density of the 15 < t < 23 class, you can use the formula:
frequency density = frequency / class width
Substituting the given values:
frequency = 1.1
class width = 8
frequency density = 1.1 / 8 = 0.1375