Understanding Normal Distribution and Z-Scores

The video tutorial explains how to determine the proportion of laptop prices within a specific range using normal distribution. It covers the calculation of z-scores for given values, the use of z-tables to find proportions, and the subtraction method to find the proportion between two values. The tutorial provides a step-by-step approach to understanding and applying these statistical concepts.

What is the mean price of the laptops in the given distribution?

• $768

• $810

• $750

• $624

What does the standard deviation of 60 indicate in the context of laptop prices?

• The highest price of laptops

• The lowest price of laptops

• The spread of prices around the mean

• The average price of laptops

In a normal distribution, where is the mean located?

• Outside the distribution

• In the center

• At the left tail

• At the right tail

What is the Z-score formula used in this context?

• (X + Mean) / Standard Deviation

• (X * Mean) / Standard Deviation

• (Mean - X) / Standard Deviation

• (X - Mean) / Standard Deviation

What is the Z-score for a laptop price of $768?

• 1.20

• 0.30

• 2.10

• 3.00

How do you find the proportion of prices below a certain Z-score using a Z-table?

• By adding the Z-score to the mean

• By multiplying the Z-score by the standard deviation

• By looking up the Z-score in the table

• By subtracting the Z-score from the mean

What is the proportion of laptop prices less than $768 according to the Z-table?

• 0.9000

• 0.6179

• 0.3000

• 0.0179

What is the Z-score for a laptop price of $624?

• -0.30

• -1.20

• -2.10

• -3.00

What is the proportion of laptop prices less than $624 according to the Z-table?

• 0.6179

• 0.0179

• 0.9000

• 0.3000

What is the final proportion of laptop prices between $624 and $768?

• 0.0179

• 0.6000

• 0.9000

• 0.3000