Sample size refers to the number of observations or data points collected in a study or survey. A larger sample size generally provides more reliable results, as it better represents the population being studied. This helps researchers draw more accurate conclusions and reduces the impact of random variation. Choosing the right sample size is crucial for statistical analysis. If the sample is too small, it may not capture the diversity of the population, leading to biased results. Conversely, an excessively large sample can be costly and time-consuming without significantly improving the findings. Proper planning is essential for effective research design.