- By
**cora** - Follow User

- 234 Views
- Uploaded on

Download Presentation
## Statistics Chapter 1

**An Image/Link below is provided (as is) to download presentation**

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

1.1 Intro to Statistics

- Statistics: the science of collecting, organizing, analyzing and interpreting data in order to make decisions
- Data - information coming from observations, counts, measurements or responses. The singular form is datum.

Data Sets

- Population: the collection of all outcomes, responses, measurements or counts that are of interest
- Sample: a subset of a population
- **it is usually impractical to obtain all of the data. In most studies, information must be obtained from a sample

Population or Sample

- Find the population and sample in each example:
- 1) 50 Mill Creek HS seniors were surveyed to find out what song they wanted for their senior song.
- 2) 2000 Republicans were polled to predict the outcome of the Republican presidential primary.

Results of Data Collection

- Parameter: a numerical description of a population characteristic
- Statistic: a numerical description of a sample characteristic
- Memory Tip: Think p for p, s for s.

Parameter or Statistic?

- 1) Of the 70 American Women surveyed, 35 said they prefer The Voice to American Idol. According to this survey, 50% of American Women prefer The Voice to American Idol.
- 2) The average professor salary at Orange Coast Community College is $45,000.

Branches of Statistics

- Descriptive Statistics: a branch of statistics that involves the organization, summarization and displaying of data.
- Inferential Statistics: branch of statistics that involves using a sample to draw conclusions about a population. A basic tool in the study of inferential statistics is probability.

Quantitative/Qualitative Data Types

- Watch out for data that looks quantitative but really isn’t! - These have no real numeric value and no meaningful order.
- Examples:
- Social security numbers
- Phone numbers
- ID #s

Quantitative/Qualitative Data Types

- What type of data is it?
- Grade point average
- Jersey Numbers of Lacrosse Players
- Hair Color
- Number of Siblings
- Student ID Number
- SAT Score
- Weight in pounds
- Movie Rating (G, PG, PG-13, R)
- Temperature in Degrees F
- Finishing place in Track event (1st, 2nd, 3rd, etc.)

Classify Data by Level - Ratio

Ratio Level - __________________ data.

Categorize, put in order, find meaningful differences, AND find ratios. Also must have a true zero. Like average rainfall. Zero rainfall means NO rain fell. 20 inches is twice as much rain as 10 inches.

Key Questions:

1)Does zero mean “none”?

- Does “twice as much” or “twice as many” make sense?

Yes to both means ratio level.

Examples: rainfall, money

Can you think of data that is ratio level?

Classify Data by Level - Interval

Interval Level - __________________ data.

Categorize, put in order, AND find meaningful differences between values. Like average temperature.

The key here is that you must be able to subtract the values to show a real difference – like, “Today was ten degrees hotter than yesterday.”

Examples: temperature, dates

Classify Data by Level - Ordinal

Ordinal Level - __________________ OR _______________ data.

Categorize AND put in order, like good, better, and best product ratings.

How else do you categorize with an order?

Classify Data by Level - Nominal

Nominal Level - __________________ data.

Categorizes things – like genres of music.

How else do you categorize things or people?

Classify – Data Level

- Nominal, Ordinal, Interval or Ratio
- 1) Is it qualitative or quantitative?

Nominal or Ordinal Ordinal, Interval, or Ratio

Classify – Data Level

- Qualitative: Nominal or Ordinal
- Can you meaningfully order it?

No Yes

Nominal Ordinal

Classify – Data Level

- Quantitative Data : Ordinal, Interval or Ratio
- 1) Does twice as much have meaning?

No Yes

Ordinal or IntervalRatio

- Meaningful numeric differences?

No Yes

OrdinalInterval

Sampling

- Sampling is a count or measure of a part of the population. Sampling produces statistics.
- The difference between a statistic and a parameter is that a statistic is obtained from a part of the population (sample), while a parameter is obtained by measuring the entire population.

Sampling TechniquesSimple Random

- Every member of the population has an equal chance of being selected

Sampling TechniquesStratified Random

- Population is separated into groups (strata) – like age groups, gender, classes, etc.
- A random sample is then selected from each strata.

Sampling TechniquesCluster

- Population is separated into groups – like age groups, gender, classes, etc.
- One or more groups is selected and ALL of the members of those groups are selected.

Sampling TechniquesSystematic

- A system (or rule) is used to select the members of the sample.
- EX: every 100th customer, the first person listed on each page of the phone book, etc.

Sampling TechniquesConvenience

- Sample is selected based on easy access for the researcher.
- EX: You survey your friends or your family, or the people sitting next to you at lunch.

Identify Sampling Techniques (cont.)

- 3. You select the first 5 people who approach you at the mall.
- 4. You assign each person a number and select every 25th person.
- 5. You survey the drama club and the track team to obtain information about student opinions on lunch choices.

Download Presentation

Connecting to Server..