Essay

Describe the mathematical correction applied when estimating a population's standard deviation from a sample, and explain the theoretical reason why this correction is necessary.

Question: Describe the mathematical correction applied when estimating a population's standard deviation from a sample, and explain the theoretical reason why this correction is necessary.

Sample answer: When researchers compute the standard deviation of a sample to estimate the variability of a larger population, they divide the sum of squared differences by N1N - 1 rather than by NN. This correction is necessary because a sample's standard deviation naturally tends to underestimate the true standard deviation of the population. Applying this N1N - 1 correction provides a more accurate estimate.

Key points:

  • State that researchers divide the sum of squared differences by N1N - 1 rather than NN.
  • Recall that a sample's standard deviation naturally tends to underestimate the true population standard deviation.
  • Explain that the N1N - 1 correction provides a more accurate estimate of the population standard deviation.

Rubric: The response must identify the correction (dividing by N1N - 1 instead of NN) and explain that a sample's standard deviation naturally underestimates the population's standard deviation, so the correction is required to produce a more accurate estimate.

0

1

Updated 2026-05-26

Contributors are:

Who are from:

Tags

KPU

Research Methods in Psychology - 4th American Edition @ KPU

Related