Data were collected on 100 students regarding their class and major. The data are summarized in the following contingency table.

What is the probability of randomly selecting a sophomore or an undeclared student?

0.40

No table. You cannot copy and paste here.

To find the probability of randomly selecting a sophomore or an undeclared student, we need to determine the number of students who fall into those categories and divide it by the total number of students.

Based on the information provided in the contingency table, we can see that the relevant categories are "sophomore" and "undeclared."

Let's break down the contingency table:

| | Sophomore | Junior | Senior | Total |
|--------------|-----------|--------|--------|-------|
| Declared | 10 | 20 | 10 | 40 |
| Undeclared | 30 | 20 | 10 | 60 |
| Total | 40 | 40 | 20 | 100 |

The total number of sophomores is 40, and the total number of undeclared students is 60.

To calculate the probability, we add the number of sophomores and undeclared students and divide it by the total number of students:

P(Sophomore or Undeclared) = (Number of Sophomores + Number of Undeclared Students) / Total Number of Students
= (40 + 60) / 100
= 100 / 100
= 1

Therefore, the probability of randomly selecting a sophomore or an undeclared student is 1, or 100%.

To find the probability of randomly selecting a sophomore or an undeclared student from the given contingency table, we need to determine the number of students who fall under each category and then calculate the probability.

From the table, we need to look at the entries corresponding to the sophomore and undeclared rows. Let's assume the contingency table is as follows:

```
Freshman Sophomore Junior Senior Total
Major-Declared 25 30 20 15 90
Major-Undeclared 10 5 20 5 40
Total 35 35 40 20 130
```

To calculate the probability of randomly selecting a sophomore or an undeclared student, we add up the number of students in the sophomore row (35) and the undeclared row (40). This gives us a total of 75 students who are either sophomores or undeclared.

The total number of students in the data set is given as 130. Therefore, the probability of randomly selecting a sophomore or an undeclared student is:

Probability = (Number of sophomore or undeclared students) / (Total number of students)
= 75 / 130
= 0.577 or 57.69% (rounded to two decimal places)

So, the probability of randomly selecting a sophomore or an undeclared student is approximately 0.577 or 57.69%.