Lecture 1

Indicate the fallacy

An older lady was asked what the secret to her health was. She said she
drinks a glass of red wine every day. So drinking a glass of red wine everyday
will help you live longer

Anecdotal evidence fallacy-Uses personal stories as proof without solid comparison.

Indicate the fallacy

Children that play more video games are more violent. Therefore video games

make you violent.

Correlation equals causation fallacy-Assumes one thing causes another just because they happen together

There is no evidence that UFOs don’t exist. Therefore, they do exist

no evidence fallacy- Claims something is true just because there’s no proof it’s false.

(I) Income Tax Brackets (e.g. $0 - $19,999, $20,000 - $49,999, $50,000 -

$999,999)

(II) Make of Car (Audi, Ford, Chevy, Kia, Hyundai, etc.)

A (I) Categorical and (II) Categorical- using categories or labels

(I) Stock Price

(II) Job Title (Clerk, Supervisor, Manager, CEO)

C (I) Ratio and (II) Ordinal [ratio true zero & Ordinal- rank/meaningful order]

(I) Student Status (whether or not you’re a student)

(II) Time in check out line at store

(I) Nominal and (II) Ratio [Nominal Level- Categorical data with no order—just names or labels and Ratio- true zero]

Indicate the sampling method.

In a factory producing tv sets, every 100th set produced is inspected

k-in-1 systematic sampling-Select every k-th person from a list (like every 10th person).

Indicate the sampling method.

An airline company randomly choose four flights from a list of all flights taking place that day. All passengers on the selected flights are asked to fill out a survey on a meal satisfaction

Cluster sampling- Randomly choose whole groups (clusters), then survey everyone in those groups.

Indicate the sampling method.

A class of 200 students is numbered 1 to 200 and a table of random digits is used to choose 60 students from the class

random sampling- Everyone has an equal chance of being chosen

Symmetry and Skewness

how a data set is shaped—symmetric if it's balanced, right-skewed if the tail stretches right (high outliers), and left-skewed if the tail stretches left (low outliers).

regression

study the relationship of two or more variables.

Identify the correlation coefficient for the plot below and Interpret it.

-0.661

Consider flipping a coin 2 times. I am interested in getting one head. What

is the sample space?

• HH (head, head)

• HT (head, tail)

• TH (tail, head)

• TT (tail, tail)

these are the possible outcomes when flipping a coin tice.

On a baseball team, nine players are designated as the

starting line up. Before a game, the coach announces the order in

which the nine players will bat. How many different orders are

possible?

9! possible orders

Find the number of ways to listen to 6 different CD’s from a selection of 18 CD’s

P(18,6)= 18!/ (18-6)!

Suppose that the pH level of water is normally distributed with a mean of

7.5 and a standard deviation of 0.8. Knowing this, approximately 95% of

water will have pH between what two values?

B: (5.9, 9.1) since we want 95% range we use formula μ−+2σ , so 7.5-2(0.8)=5.9 and 7.5+2(0.8)= 9.1

Suppose that the pH level of water is normally distributed with a mean of

7.5 and a standard deviation of 0.8. A desired pH level is between 6 and 8.5.

What is the probability it falls within this range?

formula:X-mean/ SD where X is the interest

so 6 - 7.5/ 0.8 and 8.5 - 7.5/0/8

The amount of time a bank teller spends with each customer is normally

distributed with a population mean μ = 3.2 minutes and standard deviation

σ = 0.4 minutes. If a random sample of 16 customers is selected.

what is the average of the sample means and standard error of the sample

means??

σ/ squareroot n, σ represents standard deviation & squareroot n represent. 0.4/ squareroot 16 = 0.1

Fill in the blanks: the point of a confidence interval is to use ———- data

to make a conclusion about the ———

sample, population

A recent article in The Wall Street Journal suggests that women start new businesses for freedom and flexibility, and not for money. In a survey of 625 women who had started their own business, 188 said that they launched their business for greater freedom and flexibility. Only 81 indicated that a desire to make more money drove them to start their business. We desire a 95% confidence interval of the population proportion of women who started new businesses to gain greater freedom and flexibility, which is (0.2648, 0.3368).

What is the correct interpretation?

We are 95% confident that the proportion of women who start new businesses to

gain greater freedom and flexibility is between 0.2648 and 0.3368.

I ate an uncooked hamburger, and I did not get sick, so it must not be as unsafe as people claim.

Anecdotal evidence fallacy since this person uses their personal story

There is no proof of life on other planets, so we are the only ones in the universe.

No evidence fallacy

People with tattoos tend to have a criminal record. Therefore, tattoos cause you to have a criminal record

✅ Correlation equals causation fallacy assumes a causal relationship just because two things happen together