When the confidence level of a test is increased which of the following will happen-
**Core Concept**
The confidence level of a test refers to the degree of certainty that the results are valid and reliable. Increasing the confidence level typically involves increasing the sample size, improving the study design, or using more robust statistical methods.
**Why the Correct Answer is Right**
When the confidence level of a test is increased, it means that the researcher is more confident that the results are not due to chance. This is achieved by reducing the margin of error, which is the range within which the true population parameter is likely to lie. A higher confidence level requires a larger sample size, as the increased precision reduces the variability in the estimates. This, in turn, increases the power of the test to detect statistically significant differences.
**Why Each Wrong Option is Incorrect**
**Option A:** Decreased margin of error.
Incorrect, as increasing the confidence level actually increases the margin of error, but in a way that provides a more precise estimate of the population parameter.
**Option B:** Reduced sample size.
Incorrect, as increasing the confidence level requires a larger sample size, not a smaller one.
**Option C:** Increased variability in estimates.
Incorrect, as increasing the confidence level actually reduces the variability in estimates, making them more precise.
**Clinical Pearl / High-Yield Fact**
When designing studies, researchers should carefully balance the confidence level with the sample size, as increasing the confidence level can lead to increased costs and longer study durations. It's essential to consider the trade-offs between precision and feasibility when planning research studies.
**Correct Answer:** C.