Question

A group of students were given a spelling test.

Answer 1

Answer:

1. 4
2. 30 students
3. 8.1

Step-by-step explanation:

Range of data :

• Maximum value - Minimum value
• 10 - 6
• 4

Students in the group :

• Sum of frequencies
• 5 + 4 + 7 + 10 + 4
• 9 + 7 + 10 + 4
• 16 + 10 + 4
• 26 + 4
• 30 students

Mean mark :

• 6(5) + 7(4) + 8(7) + 9(10) + 10(4) / 30
• 30 + 28 + 56 + 90 + 40
• 160 + 84 / 30
• 244/30
• 8.1

Answer 2

Answer:

a) 4

b) 30

c) 8

Step-by-step explanation:

The range is the difference between the biggest and the smallest number. The biggest mark is 10, and the smallest mark is 6.

⇒ Range = 10 - 6 = 4

To calculate how many students are in the group, add the values in the frequency column:

⇒ Total number of students = 5 + 4 + 7 + 10 + 4 = 30

To calculate the mean mark of the group, multiply each mark by its frequency, add these up, then divide by the total number of students:

⇒ Mean Mark = [ (6 × 5) + (7 × 4) + (8 × 7) + (9 × 10) + (10 × 4) ] ÷ 30

                       = [ 30 + 28 + 56 + 90 + 40 ] ÷ 30

                       = 244 ÷ 30

                       = 8.1333333333...

                       = 8 (nearest whole number)