# Study Notes #1

Date: June 27, 2022

## Descriptive Statistics

**Data**

Defined as distinct pieces of information and it can come in many forms.

Used to understand and improve things.

**Data Types**

**Quantitative**– data takes on numeric values that allow us to perform mathematical operations (like the number of dogs).**Continuous**– data can be split into smaller and smaller units, and still a smaller unit exists. An example of this is the age of the dog – we can measure the units of the age in years, months, days, hours, seconds, but there are still smaller units that could be associated with the age.**Discrete**– data only takes on countable values. The number of dogs we interact with is an example of a discrete data type.

**Categorical**– is used to label a group or set of items (like dog breeds – Collies, Labs, Poodles, etc.).**Ordinal**– data take on a ranked ordering (like a ranked interaction on a scale from`Very Poor`

to`Very Good`

with the dogs).**Nominal**– data do not have an order or ranking (like the breeds of the dog).

## Summary Statistics

**Measure of Spread** – idea of how each data differ

**Analyzing Quantitative Data**

**Four Aspects:**

- Measures of
**Center** - Measures of
**Spread** - The
**Shape**of the data **Outliers**

**Measure of Center** – idea of the average

Three widely accepted measures of center.

**Mean**–`=AVERAGE`

/ sum of all the values in the data set divided by the count of values**Median**– splits our data so that 50% of our values are lower and 50% are higher.- Arrange the data set in order – lowest to highest value
- ODD count – the median is the middle value
- EVEN count – get the mean (average) of the two middle value

**Mode**

```
5, 8, 15, 7, 10, 22, 3, 1, 15
AVERAGE = 86/9
MEAN=
```**9.56**

~~5~~, ~~8~~, ~~15~~, ~~7~~, ~~10~~, 22, ~~3~~, ~~1~~, ~~15~~
1, 3, 5, 7, **8**, 10, 15, 15, 22 = 9 COUNT
MEDIAN = 8

```
5, 8, 15, 7, 10, 22, 3, 1, 15, 2
1, 2, 3, 5,
```**7, 8**, 10, 15, 15, 2 = 10 count
7+8 = 15/2
MEDIAN = **7.5**

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