11-10 Normal Distributions

11-10 Normal Distributions

Objective: Use a normal distribution

Multiple Choice

Exercise 1. Which phrase is NOT a definition of distribute?

In your notes, cross out the phrase that IS NOT a definition.

On your computer, select the phrase that IS a definition.

• to collect or gather

• to give or hand out

If an outcome in a probability experiment can only take on whole number values, we say the outcome is discrete. If the outcome can take on any decimal value, we say the outcome is continuous.

Discrete vs. continuous

In your notes, write D for each experiment with discrete outcomes and N for each experiment without nondiscrete (continuous) outcomes.

Exercises 2 - 7

Multiple Choice

Exercises 4 and 5. How did you answer?

• 4. 4. D

  5. 5. D

• 4. 4. D

  5. 5. N

• 4. 4. N

  5. 5. D

• 4. 4. N

  5. 5. N

In your notes, write D for each experiment with discrete outcomes and N for each experiment with nondiscrete (continuous) outcomes.

Exercises 2 - 7

The normal distribution describes experiments with lots of outcomes near some mean value, some more outcomes between 1 and 2 s.d. from the mean, and only a few outcomes more than 2 s.d. from the mean.

Normal distribution

Fill in the Blanks

Exercise 8. If babies' weights are normally distributed around

a mean weight,

% of the weights should fall between the
mean and one standard deviation above the mean.

Complete Exercises 9 - 12 in your notes based on the bar graph.

Problem 1

Open Ended

Exercise 12. What percent of the female brown bears weigh less than 120 kg?

(Answers will vary a little.)

Check your answers!

Problem 1

For a population of female European eels, the mean body length is 21.1 in. The standard deviation is 4.7 in. Complete Exercises 13 - 15 in your notes.

Hint: We did something like this in Problem 3 of section 11-7.

Problem 2

Fill in the Blanks

Exercise 14. What body length is 2 standard deviations

above the mean for this population of female European eels?

Check your answers

Problem 2

Check your answers!

Problem 2

The scores on the Algebra 2 final are approximately normally distributed with a mean of 150 and a standard deviation of 15. What percentage of the students who took the test scored above 180? Try Exercises 1

Problem 3

Fill in the Blanks

Thinking Question. According to the diagram you made for Problem 3,

What percentage of students earned a score between 165 and 180?

Hint: Compare your diagram to the one at the top of page 315.

Fill in the Blanks

Exercise 20. About

% of the students who took the test scored above 180.

Check your answers!

Problem 3

Check your answers!

Problem 3