Use the standard deviation to compare the variability of the datasets. Round to the nearest hundredths.

Datasets A: 11, 7, 12, 8, 9, 5
Datasets B: 10, 8 ,10 ,8, 8, 4

1 answer

To compare the variability of the datasets A and B using standard deviation, we will calculate the standard deviation for both datasets.

Step 1: Calculate the Mean

For Dataset A: \[ \text{Mean (A)} = \frac{11 + 7 + 12 + 8 + 9 + 5}{6} = \frac{52}{6} \approx 8.67 \]

For Dataset B: \[ \text{Mean (B)} = \frac{10 + 8 + 10 + 8 + 8 + 4}{6} = \frac{58}{6} \approx 9.67 \]

Step 2: Calculate the Variance

For Dataset A:

  1. Calculate each squared deviation from the mean.

    • \( (11 - 8.67)^2 \approx 5.44 \)
    • \( (7 - 8.67)^2 \approx 2.78 \)
    • \( (12 - 8.67)^2 \approx 11.11 \)
    • \( (8 - 8.67)^2 \approx 0.44 \)
    • \( (9 - 8.67)^2 \approx 0.11 \)
    • \( (5 - 8.67)^2 \approx 13.49 \)
  2. Sum the squared deviations. \[ \text{Sum} \approx 5.44 + 2.78 + 11.11 + 0.44 + 0.11 + 13.49 \approx 33.37 \]

  3. Calculate the variance. \[ \text{Variance (A)} = \frac{33.37}{6} \approx 5.56 \]

For Dataset B:

  1. Calculate each squared deviation from the mean.

    • \( (10 - 9.67)^2 \approx 0.11 \)
    • \( (8 - 9.67)^2 \approx 2.78 \)
    • \( (10 - 9.67)^2 \approx 0.11 \)
    • \( (8 - 9.67)^2 \approx 2.78 \)
    • \( (8 - 9.67)^2 \approx 2.78 \)
    • \( (4 - 9.67)^2 \approx 32.49 \)
  2. Sum the squared deviations. \[ \text{Sum} \approx 0.11 + 2.78 + 0.11 + 2.78 + 2.78 + 32.49 \approx 41.05 \]

  3. Calculate the variance. \[ \text{Variance (B)} = \frac{41.05}{6} \approx 6.84 \]

Step 3: Calculate the Standard Deviation

For Dataset A: \[ \text{Standard Deviation (A)} = \sqrt{5.56} \approx 2.36 \]

For Dataset B: \[ \text{Standard Deviation (B)} = \sqrt{6.84} \approx 2.61 \]

Conclusion

  • Standard Deviation of Dataset A: \( \approx 2.36 \)
  • Standard Deviation of Dataset B: \( \approx 2.61 \)

After rounding to the nearest hundredths:

  • Standard Deviation A: 2.36
  • Standard Deviation B: 2.61

Comparing Variability

Dataset B has a slightly higher standard deviation than Dataset A, indicating that Dataset B has greater variability in its values compared to Dataset A.