math questions

1. What is the formula for the CI For samples sizes ≥ 100?

 2. How do we locate the Z score (on the Z table) for 95% CI?

 3. Mean = 12.4 times  S = 3.2 times    N = 120

 Construct a 95% CI around our estimate of the mean drawn from this sample.

 4. By lowering our level of confidence, we would gain some precision in our estimate.  True or False?

 5. Whenever you have a choice between a smaller or a larger sample, choose the _________ sample as your estimates (inferences) about the population will be more accurate.

a)     Larger

b)    Smaller

 6. What if the sample size is less than 100, N < 100? What is the formula for CI?

 7. When we use the T table do we use Level of Significance for a One-Tailed test or Level of Significance for Two-Tailed Test?

 8. To summarize, when do we use the Z table? When do we use the T table?

 9. How do we calculate the degrees of freedom (df)?

 10. The degrees of freedom are located in the very first column and begin with 1 and go sequentially through 30 and then moves to 40, 60, 120, and infinity.  Correct?