Practice - Standard Normal Distribution
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Practice Questions
Test your understanding with targeted questions
Calculate the Z-score for X = 80 with mean μ = 75 and σ = 5.
💡 Hint: Use the Z-score formula: Z = (X - μ) / σ.
If the mean is 100 and σ is 10, what is Z for X = 90?
💡 Hint: Subtract the mean from the value, then divide by the standard deviation.
4 more questions available
Interactive Quizzes
Quick quizzes to reinforce your learning
What is the mean of a standard normal distribution?
💡 Hint: Remember the defining properties of the standard normal distribution.
True or False: A Z-score of -1 indicates a value below the mean.
💡 Hint: Visualize the normal distribution; below the mean corresponds to negative Z-scores.
2 more questions available
Challenge Problems
Push your limits with advanced challenges
A factory produces light bulbs with an average lifespan of 800 hours and a standard deviation of 50 hours. What is the probability that a bulb lasts longer than 850 hours?
💡 Hint: Use the complement rule for values greater than the calculated Z-score.
Given a normally distributed variable representing heights of adult men with a mean of 70 inches and a standard deviation of 3 inches, what percent of men are shorter than 66 inches?
💡 Hint: Again, refer to Z-tables for cumulative probabilities for this Z-score.
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