# Stat 202: Lecture 8 (covers pp. 112-115)

Nathan VanHoudnos
10/10/2014

### Agenda

1. Homework comments
2. Checkpoint #9 results
3. Lecture 8 (covers pp. 100-111)

### Homework comments

Homework 3

• was released on Wednesday, and
• does not include any R.

Please follow the standard process for Knitting and handing in your homework through Blackboard.

Your solutions should include both symbols and English words explaining those symbols.

• follow the exmample of these slides.
• do not simply show the symbols.

### Agenda

1. Homework comments
2. Checkpoint #9 results
3. Lecture 8 (covers pp. 100-111)

### Checkpoint #9 results

• 67 of 76 students
• 75% correct

### Participation in OLI Activities

Bottom third: completed between 0 and 33% of the activities.

Middle third: 34% to 95%

Top third: 95% to 100%

### Checkpoint #9: Questions 5 - 7

According to the information that comes with a certain prescription drug, when taking this drug, there is a 20% chance of experiencing nausea (N) and a 50% chance of experiencing decreased sexual drive (D). The information also states that there is a 15% chance of experiencing both side effects.

What is the probability of

• experiencing nausea or a decrease in sexual drive?
• experiencing only nausea?
• experiencing neither of these side effects?

### Checkpoint #9: Questions 5 - 7

Make a Venn Diagram:

Recall:

20% chance of experiencing nausea (N), 50% chance of decreased sexual drive (D), and a 15% of both.

### Checkpoint #9: Questions 5 - 7

What is the probability of

• experiencing nausea or a decrease in sexual drive?
• experiencing only nausea?
• experiencing neither of these side effects?

### Two-way probability table

20% chance of experiencing nausea (N), 50% chance of decreased sexual drive (D), and a 15% of both.

Fill in the given information:

      |  D   | not D | Total
------|------|-------|------
N     | 0.15 |       |  0.20
------|------|-------|------
not N |      |       |
------|------|-------|------
Total | 0.50 |       |  1


### Two-way probability table

20% chance of experiencing nausea (N), 50% chance of decreased sexual drive (D), and a 15% of both.

Figure out the rest:

      |  D   | not D | Total
------|------|-------|------
N     | 0.15 |       |  0.20
------|------|-------|------
not N |      |       |  0.80
------|------|-------|------
Total | 0.50 | 0.50  |  1


### Two-way probability table

20% chance of experiencing nausea (N), 50% chance of decreased sexual drive (D), and a 15% of both.

Figure out the rest:

      |  D   | not D | Total
------|------|-------|------
N     | 0.15 | 0.05  |  0.20
------|------|-------|------
not N | 0.35 | 0.45  |  0.80
------|------|-------|------
Total | 0.50 | 0.50  |  1


### Plain-text Venn Diagram

Venn Diagram

Table

     |  D |not D|Tot.
-----|----|-----|----
N    | .15| .05 | .20
-----|----|-----|----
not N| .35| .45 | .80
-----|----|-----|----
Total| .50| .50 | 1


### Two-way probability table

Table

     |  D |not D|Tot.
-----|----|-----|----
N    | .15| .05 | .20
-----|----|-----|----
not N| .35| .45 | .80
-----|----|-----|----
Total| .50| .50 | 1


What is the prob. of

• experiencing nausea or a decrease in sexual drive?
• experiencing only nausea?
• experiencing neither of these side effects?

### Agenda

1. Homework comments
2. Checkpoint #9 results
3. Lecture 8 (covers pp. 100-111)

### Motivating example

All the students in a certain high school were surveyed, then classified according to gender and whether they had either of their ears pierced: