Question 1	Answer
What is Statistics?

Question 2	Answer
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What is the purpose of Statistics?

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What are the main types of data used in Statistics?

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What is the difference between descriptive and inferential Statistics?

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What is the purpose of a probability distribution?

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What is the difference between a population and a sample?

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What is a linear regression?

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What is the difference between a correlation and a causation?

Introduction to Statistics

Statistics is the study of data and how it can be used to answer questions. It is an important tool for making decisions and understanding the world around us.

In this practice sheet, you'll learn some of the basic concepts of Statistics and how to apply them to answer questions.

Data

Data is information that can be collected and analyzed. It can be numbers, words, or any other type of information.

Types of Data

Data can be classified into two main types:

Quantitative data is data that can be measured, such as age, height, or weight.
Qualitative data is data that describes a quality or characteristic, such as gender, hair color, or favorite color.

Collecting Data

Data can be collected in a variety of ways, including surveys, experiments, or observations.

Descriptive Statistics

Descriptive Statistics is a way of summarizing data, such as finding the average or the most common value.

Measures of Central Tendency

A measure of central tendency is a way to describe the middle of a set of data. The three most common measures are the mean, median, and mode.

The mean is the average of all the values in the data set.
The median is the middle value in a data set when the values are arranged in order.
The mode is the most common value in a data set.

Measures of Variation

A measure of variation is a way to describe how spread out the data is. The two most common measures are the range and the standard deviation.

The range is the difference between the highest and lowest values in the data set.
The standard deviation is a measure of how much the values in the data set differ from the mean.

Inferential Statistics

Inferential Statistics is a way of using data to make predictions or draw conclusions.

Hypothesis Testing

Hypothesis testing is a way of testing an idea or hypothesis by collecting data and analyzing it. The process of hypothesis testing includes:

State the hypothesis.
Collect the data.
Analyze the data.
Draw a conclusion.

Correlation

Correlation is a measure of how two variables are related. A correlation can be positive, negative, or zero.

A positive correlation means that when one variable increases, the other variable also increases.

A negative correlation means that when one variable increases, the other variable decreases.

A zero correlation means that there is no relationship between the two variables.

Practice Problems

Calculate the mean, median, and mode of the following data set:

2, 4, 6, 8, 8, 8, 10

Mean: 7

Median: 8

Mode: 8

Calculate the range and standard deviation of the following data set: