Chapter 9 Review

Confidence Intervals

Formula found on pg. 503 You are not using the equation with standard

deviations 1, 2, and 3. You will use z* values Critical values (z*) for 8 different confidence

levels found on pg. 502 P-hat = # said yes / # in sample

To find answer on graphing calculator: STAT, TEST, 1 PROP Z-INT. Enter values for x (# said yes), n (# in sample), and the confidence level.

Errors

Type 1: It’s right, but you say it’s wrong. (You reject, but it was true)

Type 2: It’s wrong, but you say it’s right. (You fail to reject, but it was false)

Hypotheses and Tests

Ho: Null Hypothesis: ≤, ≥, and = Ha: Alternative Hypothesis: <, >,

and ≠

To decide which “tail” test a problem uses, look at Ha:Ha is <: It’s a left tail testHa is >: It’s a right tail testHa is ≠: It’s a two tail test

Hypothesis Testing

Identifying p, p-hat, and q p is the population proportion (the

percentage that they claim is true). This is the number that is mentioned in the null and alternative hypotheses.

q is the complement of the population proportion (1-p).

p-hat is the sample proportion (the percentage that they have found during a survey)

Hypothesis Testing

You will need the Critical Values Table that uses the significance value and tail test value (found in white book on page 353…and in your notes). This will give you the critical value to serve as the barrier for your graph.

Shade the appropriate area(s) on your graph based on this barrier. The shaded area is your rejection region.

Hypothesis Testing

Z-score formula (found in white book on page 374…and in your notes)

This value will lie either in the “reject Ho” or “fail to reject Ho” region.

If it lies exactly on the critical value line, you “fail to reject Ho”.

The statement you make is in terms of the original claim (not necessarily the null hypothesis)…read the problem carefully!

Chapter 10 Material (EC)

Expected Counts – Remember how to calculate these:

(row total * column total ) / table total