Loading the lesson
Loading the lesson
Search AllRounder.ai
Search the courses, subjects, tracks, games and features, or jump straight to a page.
Search the courses, subjects, tracks, games and features, or jump straight to a page.
5 cards from this section. Quick, good the night before a test.
X is normally distributed with mean 50 and standard deviation 8. Find the z-score of x = 58.
Subtract the mean, then divide by the standard deviation.
Given P(Z < 1) = 0.8413, find P(Z < −1).
The standard normal curve is symmetric about 0.
X has mean 50 and standard deviation 8. What is the z-score of x = 42?
A value below the mean has a negative z-score.
What is P(−1 < Z < 1), using table values?
Subtract the area to the left of −1 from the area to the left of 1.
X is normally distributed with mean 50 and standard deviation 8. Find P(X < 42 or X > 58) and P(38 < X < 62), given P(Z < 1) = 0.8413 and P(Z < 1.5) = 0.9332.
The outside region is the complement of the middle region; use the symmetry shortcut for the second part.
The masses of apples from an orchard are normally distributed with mean 150 g and standard deviation 10 g. What percentage of apples have masses between 135 g and 165 g, and how many of a batch of 500 apples would you expect in this range? (P(Z < 1.5) = 0.9332)
Standardise both boundaries, then multiply the probability by 500.
6 more questions in this section. Enroll free to practise them all.
Enroll free