1. Remaining 10.1 Objectives
State in nontechnical language what is meant by a “level C confidence interval”
Explain what it means by the “upper p critical value” of the standard Normal distribution
For a known population standard deviation (that is mu) construct a level C confidence interval for a population mean.

2. List the 4 necessary steps in the creation of a confidence interval (see Inference Toolbox).
Identify three ways to make the margin of error smaller when constructing a confidence interval.
Once a confidence interval has been constructed for a population value, interpret the interval in the context of the problem.

3. Determine the sample size necessary to construct a level C confidence interval for a population mean with a specified margin of error.
Identify as man y of the six “warnings about constructing confidence intervals as you can. (For example, a nice formula cannot correct bad data.)

4. ! Be sure to check that these conditions for constructing a confidence interval for mu are satisfied before you perform any calculations.
Read and work through Example 10.4

7. These are the most commonly used z* values.
Confidence level
Tail area Z*
90%
0.05
1.645
95%
0.025
1.960
99%
0.005
2.576
These are the most commonly used z* values.

10. 2nd, VARS or DISTR
Remember that 0<C<1

11. Form of a confidence interval
(Estimate)  (margin of error)
(Estimate)  (critical value of t or z)  (standard error)

12. From Example 10.5

13. Inference Toolbox (p 631)
Step 1: Parameter Step 2: Conditions (see also p 627) Step 3: Calculations Step 4: Interpretation

16. PRACTICE: TPS 10.7, 10.9, 10.11, 10.12

17. How CI’s behave

19. Caution
There are numerous cautions on p 636 & 637… READ THEM

20. PRACTICE TPS 10.15 through 10.18 Cooperative assessment 10.1
NOTE: Calculating confidence interval is only part of the inference process. Follow the steps in the Inference Toolbox (p 631).