Final answer:
You do not need to check the entire population to make a statistical statement. Statistical inference allows using a representative sample to make predictions, but the sample must be representative for valid results. Larger sample sizes increase reliability and the confidence level of the survey results.
Step-by-step explanation:
No, you do not need to check the entire population to use a statistical statement. Statistical inference allows researchers to make predictions or draw conclusions about a population based on a representative sample.
In the context of conducting a survey with a certain confidence level, if the survey is well-designed, an appropriate sample size can be used to make reliable inferences about the entire population. However, the sample must be representative of the population to ensure the results are valid. When samples are not representative, using results to describe the entire population can lead to inaccurate conclusions.
As for whether a larger sample size is needed for a higher confidence level, the answer is yes. A larger sample will provide more reliable estimates of the population mean, making it possible to attain a higher level of confidence in the results.