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The students in Mr. McIntyre’s class and the students in Mrs. Ramos’s class were asked how many pets they each have. The dot plots below show the results.

Mr. McIntyre’s Class
A dot plot titled Mister McIntyre's Class. A number line going from 0 to 5 is labeled Number of Pets. There are 5 dots above 0, 5 above 1, 4 above 2, 1 above 3, and 0 above 4 and 5.

Mrs. Ramos’s Class
A dot plot titled Misses Ramos's Class. A number line going from 0 to 5 is labeled Number of Pets. There is 1 dot above 0, 2 above 1, 2 above 2, 4 above 3, 3 above 4, 3 above 5.

Which statement correctly compares the means of the data in the dot plots?
The mean for Mr. McIntyre’s class is about 2 more than the mean for Mrs. Ramos’s class.
The mean for Mrs. Ramos’s class is about 2 more than the mean for Mr. McIntyre’s class.
The mean for Mr. McIntyre’s class is about 1 more than the mean for Mrs. Ramos’s class.
The mean for Mrs. Ramos’s class is about 1 more than the mean for Mr. McIntyre’s class

1 answer

To find the mean number of pets for each class, we will calculate the total number of pets and divide by the number of students in each class.

Mr. McIntyre's Class:

  • Number of pets and corresponding counts:
    • 0 pets: 5 students → \(0 \times 5 = 0\)
    • 1 pet: 5 students → \(1 \times 5 = 5\)
    • 2 pets: 4 students → \(2 \times 4 = 8\)
    • 3 pets: 1 student → \(3 \times 1 = 3\)
    • 4 pets: 0 students → \(4 \times 0 = 0\)
    • 5 pets: 0 students → \(5 \times 0 = 0\)

Total for Mr. McIntyre's class: \[ 0 + 5 + 8 + 3 + 0 + 0 = 16 \text{ pets} \]

Total number of students in Mr. McIntyre's class: \[ 5 + 5 + 4 + 1 + 0 + 0 = 15 \text{ students} \]

Mean for Mr. McIntyre's class: \[ \text{Mean} = \frac{16}{15} \approx 1.07 \]

Mrs. Ramos's Class:

  • Number of pets and corresponding counts:
    • 0 pets: 1 student → \(0 \times 1 = 0\)
    • 1 pet: 2 students → \(1 \times 2 = 2\)
    • 2 pets: 2 students → \(2 \times 2 = 4\)
    • 3 pets: 4 students → \(3 \times 4 = 12\)
    • 4 pets: 3 students → \(4 \times 3 = 12\)
    • 5 pets: 3 students → \(5 \times 3 = 15\)

Total for Mrs. Ramos's class: \[ 0 + 2 + 4 + 12 + 12 + 15 = 45 \text{ pets} \]

Total number of students in Mrs. Ramos's class: \[ 1 + 2 + 2 + 4 + 3 + 3 = 15 \text{ students} \]

Mean for Mrs. Ramos's class: \[ \text{Mean} = \frac{45}{15} = 3 \]

Comparing the Means:

  • Mean for Mr. McIntyre's class \( \approx 1.07 \)
  • Mean for Mrs. Ramos's class \( = 3 \)

Now we compare: \[ 3 - 1.07 \approx 1.93 \]

Thus, the mean for Mrs. Ramos's class is about 2 more than the mean for Mr. McIntyre’s class.

The correct statement is: The mean for Mrs. Ramos’s class is about 2 more than the mean for Mr. McIntyre’s class.