Q.2.111 - Elementary Statistics

Question

Exam Scores. The exam scores for the students in an introductory statistics class are as follows.

a. Group these exam scores, using the classes $30-39,40-49,50-59, 60-69,70-79,80-89$, and $90-100$.

b. What are the widths of the classes?

c. If you wanted all the classes to have the same width, what classes would you use?

Step-by-Step Solution

Answer

a). The group of distribution is,

$\begin{array}{rr}\text{ Class }& \text{ Frequency }\\ 30-39& 2\\ 40-49& 0\\ 50-59& 0\\ 60-69& 3\\ 70-79& 3\\ 80-89& 8\\ 90-100& 4\end{array}$

b). With the exception of the last class, which has a width of $10$, all of the classes have a width of $9$.

c). The last class need to be replaced by the two classes $99-90$ and $100-109$.

Part (a) Step 1: Given Information

The data is given as,

Part (a) Step 2: Explanation

The group distribution is,

$\begin{array}{rr}\text{ Class }& \text{ Frequency }\\ 30-39& 2\\ 40-49& 0\\ 50-59& 0\\ 60-69& 3\\ 70-79& 3\\ 80-89& 8\\ 90-100& 4\end{array}$

Part (b) Step 1: Given Information

The data is given is,

Part (b) Step 2: Explanation

With the exception of the last class, which has a width of $10$, all of the classes have a width of $9$.

Part (c) Step 1: Given Information

The data is given as,

Part (c) Step 2: Explanation

The last class need to be replaced by the two classes $99-90$ and $100-109$.