unit 1 statistics part 2 - PROBABILITY

Fundamental Concepts

Example

• Researchers evaluating a new depression treatment want to know if it

effectively lowers depression in all people with depression, called the

population of people with depression.

Hypothesis Testing

• Null hypothesis testing

• Significance testing

• Sampling error

Population and Samples

• Population

• Parameter

• Sample

• Statistic

• Random Sample

• Inferential Statistics

• Descriptive Statistics

Independent and Dependent Variables

• Independent Variable

• Dependent Variable

Scales of Measurement

• Nominal

• Ordinal

• Interval

• Ratio

Scale of Measurement What the Scale Allows You to Do Examples

Nominal COUNT the number of things within

different categories Pets: 5 dogs, 12 cats, 7 fish, 2 hamsters

Marital status: 12 married, 10 divorced, 2 separated

Ordinal RANK some things as having more

of something than others (but NOT QUANTIFY how much of it they have)

Annual income: above average, average, or below average

Speed (measured by place of finish in a race): 1^st, 2^nd, 3^rd, etc.

Interval QUANTIFY how much of something

there is but a score of zero does not mean the absence of the thing

being measured

Temperature: -2^o F, 98^o F, 57^o F; 0^o F is not the absence of heat

Ratio QUANTIFY how much of something

there is and a score of zero means the absence of the thing being measured

Annual income: $25,048, $48,802,

$157,435, etc.

Number of text messages sent in a day: 0, 3351, 15, etc.

Discrete and Continuous Variables

• Discrete Variables

• Continuous Variables

What next?

• Quiz time!

• Finish and submit the Assignment #1

• Complete the questionnaire for those who haven’t

• Read the Unit 2 modules