2. Info 17 more class meetings – Seniors, 19- Juniors 5 more quizzes
4 more homework assignments
2 projects
1 Final Exam
Turn in the trivia assignment from Thursday

3. Quiz #10 Trivia Q: “How many moons does Saturn have?”
Data collected: 32, 41, 37, 55, 61, 44, 48
Calculate the average answer
Calculate the Sx (standard deviation)
Identify the t* for a 90% confidence interval
Calculate a 90% confidence interval
Calculate a 99.9% confidence interval

4. What is statistical inference?
Uses data from a sample to draw conclusions about a population
A test asks if ample data give good evidence against a claim.

5. Is this deck fair?
If a deck is fair, then the actual proportion of red cards in the deck is p=____. For each deck, we are going to assume that the deck is fair.
Draw cards until we reach a consensus on the proportion p of red cards in the deck. Do you think this deck is fair?
"Do you believe that there is a 50% chance for drawing a red card with this deck?"
12 The students all say no. Then say:
--> "I agree. Now, is it possible that a person with a normal deck of half red and half black cards could pull out 10 red cards in a row?"
13 The students all chime in "yes".
--> "Is it very likely that a person would pull out 10 red cards if the deck were half red?"
14 Again, all the students say "no". (At this point, if the instructor has discussed binomial probabilities, students in the class can calculate the probability of all red cards, which in this demonstration serves to represent the p-value.)
--> "Now, we have two seemingly contradictory pieces of information about the deck of cards. We have a claim that p=0.5, and we have done an experiment in which 10 out of 10 cards chosen were red. The data which we collected seem 'inconsistent' with the hypothesis. That is, if the hypothesis were true, it would be very unlikely to have all 10 chosen cards be red. And yet, in our experiment, we selected 10 red cards. What should we conclude?"
15 The students should say that it does not seem likely that "p=0.5" is reasonable, given that all 10 chosen cards were red.
16 The instructor then begins a discussion about hypothesis testing. The important things to discuss, in my view, are:

6. Prom
I believe that more than 60% of seniors are going to prom. Does this data provide convincing evidence of that?

8. Going to the Prom?
The prom committee wants to know how many seniors they can expect to attend the prom so that they can develop a budget. An SRS of 50 of the 750 seniors yielded 36 who said they plan to attend the prom.

9. Shooting Free Throws
A friend of yours claims to make 80% of his free throws. “Show me,” you say. He shoots 20 free throws and makes 8 of them. Do you believe his claim?
Your reasoning is based on asking what would happen if the shooter’s claim were true and we repeated the sample of 20 free throws many times – he would almost never make as few as 8. This outcome is so unlikely that it gives strong evidence that his claim is not true.
You can say how strong the evidence against the shooter’s claim is by giving the probability that he would make as few as 8 out of 20 free throws if he really makes 80% in the long run. This probability is

12. Do people care if their coffee is fresh vs instant?
I believe that half of all coffee drinkers prefer fresh-brewed coffee.
We take a SRS of 50 subjects and have them taste unmarked coffee (one instant, the other freshly brewed) and record which one they prefer. 36 of our subjects choose the fresh coffee.
Is this enough evidence to say that proportion of people who prefer fresh coffee is more than half?

13. Roulette A roulette wheel has 18 red slots among its 38 slots.
You take a SRS of 50 spins. The ball landed in a red slot 31 times.
Does this data provide enough evidence that the actual proportion of times the ball lands in red is different than claimed?

14. The smoking rate for the general population is about 27%
The smoking rate for the general population is about 27%. You take a random sample of 785 college students and find that 194 smoke. Is this sufficient evidence to think that the rate is different from that of the population?

16. In 2005, researchers studies the physical fitness of adolescents aged 12 to 10 years. Of the 2205 randomly tested, 750 showed a poor level of cardiovascular fitness. Does this sample provide support for the claim that more than 30% of adolescents have a low level of cardiovascular fitness?

18. A manufacturer of a special bolt requires that this type of bolt have a mean shearing strength in excess of 110 lb. To determine if the manufacturer’s bolts meet the required standards a SRS of 35 bolts was obtained and tested. The sample mean was lb and the sample standard deviation was 9.62 lb. Use this information to perform an appropriate hypothesis test with a significance level of 0.05.

20. A blogger claims that US adults drink an average of five 8-oz glasses of water each day. You think it is less than the blogger claims and take a random sample of 24 adults.
Assume that the graph of your sample data shows a mound shape with no outliers. Your sample mean is glasses with standard deviation of

21. A jeweler is planning on manufacturing gold charms
A jeweler is planning on manufacturing gold charms. His design calls for a particular piece to contain 0.08 ounces of gold. The jeweler would like to know if the pieces that he makes contain (on the average) 0.08 ounces of gold. To test to see if the pieces contain 0.08 ounces of gold, he made a sample of 16 of these particular pieces and obtained the following data.

22. I don’t believe that human body temperature really is 98.6°F. To test my theory, I take a random of sample of 130 people and measure their temperature. The sample mean is 98.25°F and the standard deviation is 0.73°F. Is there sufficient evidence to claim that human body temperature is not 98.6°F?