I’m given 20 data points from a sample in a population that is normally distributed and asked to calculate a 94% confidence interval. My question is what to do with standard deviation since it’s not given. Can I still use a Z score in calculating margin of error or do I need to calculate a t-score, and if so, how do I do that and what is the formula?

Calculating Margin Of Error, Confidence Interval, Margin Of Error, Population, Standard Deviation, T Score, Z Score