Which statement best describes why multiple trials are conducted in an experiment?

Which statement best describes why multiple trials are conducted in an experiment?

• A. To broaden the range of independent variables.
• B. To manipulate the dependent variable.
• C. To use more data from the same condition.
• D. To increase reliability by averaging results across repetitions.

Answer: (D)

Repeating measurements is about improving reliability by reducing the influence of random fluctuations. Each trial can be affected by small, uncontrollable factors—like tiny measurement errors or slight changes in conditions. By performing multiple trials and averaging the results, these random differences tend to cancel out, giving a more accurate and stable estimate of how the variables relate. That’s why this approach increases reliability and precision. Broadening the range of variables, manipulating the outcome, or just collecting more data from the same condition without averaging don’t directly address consistency and precision in the same way.

Repeating measurements is about improving reliability by reducing the influence of random fluctuations. Each trial can be affected by small, uncontrollable factors—like tiny measurement errors or slight changes in conditions. By performing multiple trials and averaging the results, these random differences tend to cancel out, giving a more accurate and stable estimate of how the variables relate. That’s why this approach increases reliability and precision. Broadening the range of variables, manipulating the outcome, or just collecting more data from the same condition without averaging don’t directly address consistency and precision in the same way.