Unit 8

Question 1

The higher percent confidence we choose, the _______ the margin of error (m) will be.

Answer 1

Higher.

Question 2

What table do we use to find confidence intervals?

Answer 2

Table 4: t* has confidence intervals at the bottom.

Question 3

How do you find degrees of freedom for t?

Answer 3

n-1

Question 4

There are 2 formulas for finding the confidence interval for the population mean (u):

Answer 4

• x bar (plus or minus) z* multiplied by o/square root of n

- x bar (plus or minus) t* multiplied by s/square root of n

Question 5

How do you know when to use z* or t*?

Answer 5

If o (the standard deviation) is given, you can use z*.
If it is not given, you must use t*.

Question 6

What is the margin of error (m)?

Answer 6

In the formulas for confidence intervals, it is everything after x bar is plus or minus.

Question 7

How can we find sample size if it isn’t given?

Answer 7

n = (z* multiplied by o/m)^2

Question 8

What is the critical value?

Answer 8

Z*