The Data Analyst's Toolbox

Question 1

What are some common tools used for data analysis

Answer 1

• spreadsheets
• query Languages
• visualization tools

Question 2

What is a spreadsheet?

Remember working in Excel

Answer 2

A digital worksheet that
* stores
* organizes
* sorts
data

Question 3

What are some ways a spreadhseet helps a data analyst?

Answer 3

It helps them:
* see patterns
* group information
* create data visualizations

Question 4

What are formulas in spreadsheets?

Answer 4

Mathematical equations/instructions used to perform specific calculations

Question 5

What are functions in spreadsheets?

Answer 5

Preset/Predefined formulas that automatically perform a calculation/task

they cannot be internally edited / are fixed
eg SUM(argument1, argument2,…)

Question 6

What is a query language?

Answer 6

It is a **computer prpgramming language ** that allows one to retrieve and manipulate data from a database.

Question 7

Why is Structured Query Language a widely used language

Answer 7

It is easy to understand and works well with many kinds of databases.

Question 8

What are some uses of query languages?

Answer 8

They allow analysts to select, retrieve, request for, create, add, delete and update data.

Question 9

What are data visualizatioon tools used for?

Think of the Tableu Viz of the day

Answer 9

• turning complex numbers into a story
• help stakeholders come to conclusions leading to informed data driven decisions and strategies.

Question 10

Give two example of data visualization tools.

Answer 10

1. Tableu - has drag and drop features to create visuals
2. Looker- communicates directly with database and connects data to visual tool.

Question 11

Overall, what determined which tool to use in the data analysis process between databases and spreadsheets?

Answer 11

criteria based on numerous factors such as
* number of users,
* type of data
* availability
* analytical steps required

Question 12

When is it ideal to use a database?

Answer 12

When dealing with large amounts of complex data with multiple dimensions.

Question 13

What are some advantages of databases?

Answer 13

1. Unlimited amount of data
2. Ability to build relations and link data across tables
3. Efficiently hosting multiple users
4. Suitable when data is over 100 rows
5. Information can automatically update itself across all tables
6. Summary reports - since all tables are linked

Question 14

What are some limitations of databases?

Answer 14

1. Only give output in a standard table form (thus limited in visuals)
2. Have limited calculation abilities.

Question 15

What are some advantages of spreadhseets?

Answer 15

1. Can perform complex calculations and analyses.
2. Have in-built visualization tools
3. Suitable for finance (straightforward number crunching) and data analysis

number crunching- like profit, total sales

Question 16

What are some limitations of spreadsheets?

Answer 16

1. Limited in relating and connecting data especially across tables and different files.
2. One has to manually enter data
3. Becomes challenging when data exceeds 100 rows.

Question 17

Every programming language follows a predetermined set of guidelines and structure known as,

Answer 17

Syntax

Question 18

What is the basic structure of an SQL Query?

Answer 18

SELECT (columns)
FROM (dataset.table)
WHERE (conditions);

it is more efficient to select only what you need.
semicolon (;) **statement terminator **

Question 19

Write an SQL query selecting the columns that contain a customer’s first name, last name and ID from the customer name table in the customer data dataset. Furthermore, write one to retrieve customer data from a customers whose first name is Tony.

Answer 19

SELECT
first_name,
last_name,
customer_ID

FROM
customer_data.customer_name

WHERE
first_name= ‘Tony’;

Question 20

Write an SQL query selecting the columns that contain a customer’s first name, last name and ID from the customer name table in the customer data dataset. Furthermore, write one to retrieve customer data from a customers whose first name is Tony, last name Magnolia and customer id is greater than 0.

Answer 20

SELECT
first_name,
last_name,
customer_ID

FROM
customer_data.customer_name

WHERE
first_name= ‘Tony’
AND last_name= ‘Magnolia’
AND customer_ID > 0;

customer_ID > 0 is a logical condition

Question 21

True or False

Using indentation and capitalization in SQL helps one to review and troubleshoot their code more easily.

Answer 21

True

Question 22

Write a WHERE command that looks for all names that start with ch

Answer 22

SELECT *
FROM customers.customers_name
WHERE first_name LIKE ‘ch%’;

% is a **wildcard **

Question 23

To save on time when reviewing long, complex queries after a long time one should write what alongside their code?

Write an example comment on SELECT colomns

Answer 23

Comments

SELECT columns – this is customer name
SELECT columns /* */

Question 24

True or False

Comments can be written outside a query statement and within

Answer 24

True

Question 25

Write an SQL statement to assign a new alias to a column known as field 1 to first name.

(let it be known as)

Answer 25

field_1 AS first_name – Alias to assign new name

AS clause

Question 26

True or False

Aliases do not inherently change the name and they only last within the query.

Answer 26

True

Question 27

What does this command mean.
WHERE first_name <> ‘John’

Answer 27

where first name is not equal / not John.