PS_Unit 3_The Bell Curve & Empirical Rule

What is the primary difference between a parameter and a statistic?

• A number describing data from a sample vs. a number describing data from a population.

• A number describing data from a population vs. a number describing data from a sample.

• A measure of central tendency vs. a measure of spread.

• A value that is always known vs. a value that is estimated.

Which symbol represents the population mean?

• X̄

• S

• μ

• σ

In a normal distribution, what does the population mean (μ) characterize?

• The spread of the distribution.

• The position of the distribution.

• The height of the curve.

• The total area under the curve.

What aspect of a normal distribution is characterized by the population standard deviation (σ)?

• The central tendency of the data.

• The symmetry of the curve.

• The spread of the distribution.

• The number of peaks in the curve.

For a population of university students whose heights are normally distributed with a mean of 5.5 feet and a standard deviation of 0.5 feet, what percentage of students have a height between 5.0 and 6.0 feet?

• 34%

• 68%

• 95%

• 99.7%

In a normal distribution with a mean of 5.5 feet and a standard deviation of 0.5 feet, what percentage of the population falls between 4.5 and 6.5 feet?

• 68%

• 95%

• 99.7%

• 50%

A normal distribution has a mean of 70 and a standard deviation of 10. What is the approximate area contained between 60 and 80?

• 34%

• 68%

• 95%

• 99.7%

For a normal distribution with a mean of 0 and a standard deviation of 1, what is the approximate area contained between -1 and 2?

• 81.5%

• 68%

• 95%

• 47.5%