Let's analyze the problem step by step. The problem is in Croatian, so I'll first translate it into English and then solve it for you.

Problem Translation:

22. The graph shows how many children in a school have a specific number of grades from 0, 1, 2, 3, to 4 grades.

The x-axis represents the Number of Grades, and the y-axis represents the Number of Students.

Number of Grades (x)	Number of Students (y)
0	10
1	35
2	75
3	101
4	62

22.1. Calculate the average number of grades per student.
Answer:

22.2. How many students have at least one grade?
Answer:

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Step 1: Calculate the Average Number of Grades per Student

To calculate the average number of grades per student, you use the following formula:

$\text{Average} = \frac{\sum (\text{Number of Grades} \times \text{Number of Students})}{\sum \text{Number of Students}}$

Let's calculate this step by step:

1. Multiply each number of grades by the corresponding number of students:

$0 \times 10 = 0$ $1 \times 35 = 35$ $2 \times 75 = 150$ $3 \times 101 = 303$ $4 \times 62 = 248$

2. Sum these products:

$0 + 35 + 150 + 303 + 248 = 736$

3. Find the total number of students:

$10 + 35 + 75 + 101 + 62 = 283$

4. Calculate the average number of grades per student:

$\text{Average} = \frac{736}{283} \approx 2.6$

So, the average number of grades per student is 2.6.

Step 2: Calculate How Many Students Have At Least One Grade

To find out how many students have at least one grade, you sum the number of students who have 1, 2, 3, or 4 grades:

$35 + 75 + 101 + 62 = 273$

So, 273 students have at least one grade.

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Summary of Answers:

• 22.1. The average number of grades per student is 2.6.
• 22.2. The number of students who have at least one grade is 273.

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Questions to Think About:

1. How would the average change if the number of students with 0 grades increased?
2. What is the percentage of students who have exactly 4 grades?
3. How would the calculation change if another grade level (e.g., 5 grades) was added?
4. How could this data be visually represented other than a bar graph?
5. What might be some reasons for students having 0 grades?

Tip:

When working with averages, always ensure you account for all elements in the data set, and double-check your total counts to avoid mistakes in your final calculations.