Use mean and standard deviation to fit normal distributions and estimate population percentages with technology.
Compute a normal area to four decimals
Problem
For \(X~~N(80,~5)\), compute \(P(X~<~85)\). Give the \(\operatorname{normalcdf}\) setup, decimal probability, and percent interpretation.
Big Picture
What this problem is really about
Sketch the requested normal region conceptually before entering technology so the inequality determines the correct lower and upper bounds. Supply those bounds first, followed by the mean and positive standard deviation, and use a z-score as a direction-and-scale check. Keep full calculator precision until the requested rounding, then translate the area into a contextual percentage.
Inside Gozunta
Turn the preview into practice.
More than a preview
Gozunta lets you study this problem—and more than 10,000 others.
Create targeted learning sessions, use hints, check your answer, read the walkthrough, watch the video, print the work, and track your progress.
