1. Warm UP Read the Perfect Potatoes Example on P. 548
On TV shows like American Idol, contestants often wonder if there is an advantage to performing last. To investigate, researchers selected a random sample of 600 college students and showed each student the audition video of 12 different singers. For each student, the videos were shown in random order. So we would expect approximately 1/12 of the students would prefer the last singer they view, assuming the order doesn’t matter. In the study, 59 of the 600 students preferred the last singer they viewed. Calculate the z score. Do these data provide convincing evidence at the 5% significance level that there is an advantage to going last?

2. More “Perfect Potatoes”
One Potato, Two Potato (p. 559) Answer the question posed in the beginning of the example. (Don’t peak at the solution at the end!) 

3. Two-Sided Tests
The P-value in a one-sided test is the area in one tail of a standard Normal distribution—the tail specified by Ha.
In a two-sided test, the alternative hypothesis has the form
Ha : p ≠p0.
The P-value in such a test is the probability of getting a sample proportion as far as or farther from p0 in either direction than the observed value of
As a result, you have to find the area in both tails of a standard Normal distribution to get the P-value.
Let’s take a look at the Alternate Example: Benford’s law and fraud in your notes.

4. Why Confidence Intervals Give More Information
The result of a significance test is basically a decision to reject H0 or fail to reject H0. When we reject H0, we’re left wondering what the actual proportion p might be. A confidence interval might shed some light on this issue.
Taeyeon HS found that 90 of an SRS of 150 students said that they had never smoked a cigarette. The number of successes and the number of failures in the sample are 90 and 60, respectively, so we can proceed with calculations.
Our 95% confidence interval is:
We are 95% confident that the interval from to captures the true proportion of students at Taeyeon’s high school who would say that they have never smoked a cigarette.

5. Why Confidence Intervals Give More Information
There is a link between confidence intervals and two-sided tests.
The 95% confidence interval gives an approximate range of p0’s that would not be rejected by a two-sided test at the α = 0.05 significance level.
A two-sided test at significance level α (say, α = 0.05) and a 100(1 –α)% confidence interval (a 95% confidence interval if
α = 0.05) give similar information about the population parameter.