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STATS - Ch. 1 Review
Nightingale Intro to Statistics, Week 1 Summary of Sampling&Data Formulae
| Statistics is the science of collecting, organizing, and interpreting data. |
| Statistics are the data (numbers or other pieces of information) that describe or summarize something. |
| Descriptive Statistics presents summarized data |
| Inferential Statistics attempts to describe a population after viewing only a small portion |
| The population in a statistical study is the compete set of people or things being studied. |
| A population parameter summarizes the value of a specific variable for a population. |
| A sample is a subset of the population from which data are actually obtained. |
| A sample statistic summarizes the value of a specific variable for sample data. |
| A statistical study suffers from bias if its design or conduct tends to favor certain results. |
| A representative sample is a sample in which the relevant characteristics of the sample members are generally the same as the characteristics of the population. |
| A census is the collection of data from every member of a population. (not a sample) |
| A random sampling occurs if a sample is drawn in such a way that each time an item is selected, each item has an equal chance of being drawn. |
| When a sample is obtained by drawing every nth item on a list or production line, the sample is a systematic sample. |
| A cluster sample is sometimes referred to as an area sample because it is frequently applied on a geographical basis, or location. |
| Stratified sampling involves dividing the population by characteristics called stratifying factors such as gender, race, religion, or income. |
| Convenience sampling uses data that are easily or readily obtained, and can be extremely biased, and so not a representative sample. |
| Qualitative data is grouped into a category or group. Sums, products or other numerical calculations do not mean anything. |
| Quantitative Data has a value or a numerical measurement for which you can calculate sums, products and other numerical calculations. |
| Nominal: Data is put in categories (names), i.e. Color like: blue, red, yellow |
| Binary: Specific kind of Nominal, values are True/False, 1/0, Yes/No, or other similar values. |
| Ordinal: Nominal plus the data is put in ordered categories (ranks), i.e. Sizes like: small, medium, large |
| Discrete data can take on only particular, distinct values and not values in between (can be interval or ratio) |
| Continuous data can take on any value in a given interval (can be interval or ratio) |
| Interval: Ordinal plus the interval is meaningful, but ratios are not (the zero location is arbitrary), i.e. temperature in Fahrenheit or Celsius, Shoe size, women’s clothing size |
| Ratio: Interval plus the data have an absolute zero point (ratios are meaningful), i.e. height, length, etc. |
| Frequency Distribution is a chart which includes how many (frequency) of each piece of data (category) |
| Category (column), can be class, bin, range, etc. |
| Frequency (column) is how often the data occurs. |
| Tally (optional) sometimes used to make it easier to sort the data. |
| Total (row) is the total of each column. |
| Cumulative Frequency (column) is the sum of the data to that row, so the last data row should have the same value as the Total row.The cumulative frequency for row 1 is the frequency of row 1. |
| The cumulative frequency for row 2 is the frequency of row 1 + row 2. The cumulative frequency for row 3 is the Cumulative Frequency from row 2 + row 3. The cumulative frequency for row n is the Cumulative Frequency from row n-1 + row n. |
| Relative Frequency (column) of a row is the percent of that row compared to all the data. frequency for now/total frequency |
| Cumulative Relative Frequency (column), or Relative Cumulative Frequency you can either sum the Relative Column, or find the Relative Frequency of the Cumulative Column (both are the same) |