In: Statistics and Probability
To find a critical value for z-scores, go to the Probability Calculator in Geogebra. Make sure you are using the standard Normal distribution (with μ=0,σ=1). Select a right-sided interval. Convert the confidence level to decimal, and enter (1−CL)/2 in the area/proportion box. This is what the text calls α/2. For example, a 95% confidence level would use (1−.95)/2. Don’t forget the parentheses! The critical value appear inside of P( ). Find the critical z-score value for each of the following confidence levels. Round each answer to four decimal places. The z-critical value for a(n) 70% confidence level is: 0.30 equation editorEquation Editor The z-critical value for a(n) 80% confidence level is: 1.281 equation editorEquation Editor The z-critical value for a(n) 90% confidence level is: equation editorEquation Editor The z-critical value for a(n) 95% confidence level is: equation editorEquation Editor The z-critical value for a(n) 99% confidence level is: