Download Day 1: Introduction to Significance Testing

AP Stat Unit 10
Video 25
Introduction to Significance Tests
Name _____________________
Date _____________________
1. The evidence in the Shakespeare
research fails to prove that Shakespeare
did not write the poem in question.
Like a _______________ test, it can rule ___________, it can't rule____________.
2. Shakespeare's scribe was possibly an early witness to this poem. (Circle one)
T/F
According to the research, this could be by Shakespeare; there is no strong reason to doubt it.
3. “A Song” was included in Shakespeare's works. Do you agree or disagree with this decision?
4. Calculations:  = 7 new words
x = 8.2
Using the correct symbols, what is Ho?
Using the correct symbols, what is Ha?
5. Notice that Ho and Ha are always stated in terms of (parameters, statistics - circle one) and never in
terms of (parameters, statistics - circle one).
6. What is the difference between a "one-sided" and "two-sided" significance test?
7. In a significance test, we start by assuming that ___________ is true.
8. T/F
T/F
Next, we find the probability of getting a result as extreme as ours if Ho is really true.
The Sampling Distribution of x is not relevant to tests of significance.
9. In this case, we want the probability in both directions. Why?
10. What is the formula for z when working with means
(like in the case of Shakespeare's alleged poem)?
z=
This z value is called the ________________________
11. The observed value of the test statistic in this case is _____________.
12. P-Value: We follow the usual steps and look up the corresponding PRB to our z-score to get
0.1515. Why is this value multiplied by 2 in this instance?
12b. When wouldn't we multiply the PRB (area under the curve) by 2?
13. Interpretation: There is a 30.3% chance that random variation would produce a mean new word
count as far as 8.2 from his usual count. So we can expect such a result just less than 1 time out of 3.
Do we REJECT or FAIL TO REJECT (circle one) the _______ hypothesis.
14. Explain in clear language what your answer to #13 means for the Shakespeare poem.
15. Why do small p-value give evidence to reject the null hypothesis?
16. What does it mean to say "Statistically Significant at the 5% level."