# Statistics

Get Started. It's Free
Statistics

## 1. Descriptive statistics

### 1.1. Sample

1.1.1. Distribution of Scores

1.1.1.1. Frequencies

1.1.1.1.1. Frequency table

1.1.1.1.2. Frequency graph

1.1.1.2. Non-normal distribution

1.1.1.2.1. Kurtosis

1.1.1.2.2. Skewedness

1.1.1.2.3. Multi-modal

1.1.1.3. Normal distribution

1.1.1.3.1. Z-Scores

1.1.2. Central Tendency

1.1.2.1. Mean

1.1.2.2. Median

1.1.2.3. Mode

1.1.3. Variability

1.1.3.1. Range

1.1.3.2. Sum of Squares

1.1.3.2.1. Variance

## 2. Inferential statistics

### 2.1. Use the sample to infer info about the population.

2.1.1. Probability

2.1.1.1. Outcome of Interest/Total Possible Outcomes

2.1.1.1.1. Ranges from 0 to 1 (.5 being 50/50 chance)

2.1.1.1.2. "And" Probability

2.1.1.1.3. "Or" Probability

### 2.2. Sampling procedures

2.2.1. Haphazard selection

2.2.2. Convenience sample

2.2.3. Snowball sampling

### 2.3. Above all, we want our sample to be representative of our population.

2.3.1. The best way to ensure this is through random sampling.

2.3.1.1. When we can't ensure random sampling, the best we can do is make sure the sample isn't systematically unrepresentative.

## 3. Variables

3.1.1. Scores

### 3.2. Levels of measurement

3.2.1. Qualitative

3.2.1.1. Nominal

3.2.2. Quantitative

3.2.2.1. Ordinal

3.2.2.2. Interval

3.2.2.3. Ratio

3.2.3. Discrete

3.2.3.1. Nominal

3.2.3.2. Ordinal

3.2.4. Continuous

3.2.4.1. Interval

3.2.4.2. Ratio