Question

statistical modeling – end of 9 weeks part b - sep 25, 2025
answer all the following questions:

1. what is the width of the class 20.7 - 28.3?

a. 7.7 b. 7.6 c. 28.35 d. 24.5

1. what are the boundaries of the class 2.15 - 3.65?

a. 2.1 - 3.7 b. 2.14 - 3.66 c. 2.149 - 3.659 d. 2.145 - 3.655

1. the following frequency distribution was obtained.

class boundaries frequencies
17.5 - 22.5 5
22.5 - 27.5 7
27.5 - 32.5 10
32.5 - 37.5 12
37.5 - 42.5 13

Explanation:

Step1: Calculate class - width for question 1

The formula for class - width is $upper - class - limit - lower - class - limit$. For the class $20.7 - 28.3$, we have $28.3−20.7 = 7.6$.

Step2: Determine class boundaries for question 2

The lower class boundary is found by subtracting $0.005$ from the lower class limit and the upper class boundary is found by adding $0.005$ to the upper class limit. For the class $2.15 - 3.65$, the lower class boundary is $2.15 - 0.005=2.145$ and the upper class boundary is $3.65 + 0.005 = 3.655$.

Answer:

1. b. 7.6
2. d. 2.145 - 3.655