1. Determine the sample size needed to estimate the population mean within a level of precision of 0.03, a standard deviation of 0.5, and a 95% confidence level. 2. A researcher wants to know the mathematical performance of the Grade 12 Statistics students under the cooperative learning teaching strategy. She wants to estimate the population mean within an error of 4% of its true value and a confidence level of 95%. Previous studies showed that the standard deviation is 0.25. Find the required sample size to estimate the population mean.