Data Science Exam #3

interactive dashboards

An interactive dashboard is a dashboard that gives multiple perspectives to the data rather than just one data visualization.

How does confidence interval change when choosing 90% level instead of 95%?

As the confidence level increases the width of the confidence interval also increases. A larger confidence level increases the chance that the correct value will be found in the confidence interval.

What is the difference between Hadoop and MapReduce?

Hadoop stores big databases in small pieces across a network of connected computers, stores files and processes data MapReduce works together within Hadoop, breaks up tasks, and gives each connected computer a small piece to work on.

What is the confidence (prediction) interval? What does it tell us?

The prediction interval predicts in what range a future individual observation will fall, while a confidence interval shows the likely range of values associated with some statistical parameter of the data, such as the population mean.

What is machine learning?

Machine learning is a broad category of techniques to learn model parameters from data so that the model can be used to predict values or classify items.

data sorting

Sorting data, you are putting it in order

How does sentiment analysis software determine a positive/negative score for a block of text?

looks for positive or negative words like "good" and "amazing" or "bad" and "terrible"

What factors influence the confidence interval of a trend line (i.e., the Tableau exercise)?

size of samples, variability, confidence level- higher level will tend to make a more confident trend.

What are some examples of structured and unstructured data?

structured - price of an online product, product name and description unstructured - reviews of an online product, picture, video

Descriptive Analytics

summarizes past data, what has happened?

How do they facilitate the analysis of Big Data?

they process big data and determine what to do with it

What is a word frequency analysis? What insight can it give you about a block of text?

a table of different words used in a block of text tells the main point of text. measures the most commonly used words in a text and it helps because you can see whether something is mainly positive or negative for example.

pivot table analysis

A pivot table is a table of statistics that summarizes the data of a more extensive table (such as from a database, spreadsheet, or business intelligence program). This summary might include sums, averages, or other statistics, which the pivot table groups together in a meaningful way.

What is the difference between descriptive, predictive, and prescriptive analytics?

Descriptive analytics = summarizes past data, what has happened? Predictive analytics =forecast of what may happen in the future, what could happen in the future based on the past? Prescriptive analytics = helps facilitate decision-making, what should a business do?

In what situations can sentiment analysis be inaccurate?

Different language, usage (ie. awfully good)

What is analytics?

Extracting information from data and discovering meaningful patterns

data Filtering

Filtering data lets you hide unimportant data

How is data stored for pivot table analysis?

PivotTables contain a column for each field and a row for each data record

What are the benefits of sentiment analysis?

companies and individuals can monitor their reputation and get feedback on products and actions

What is sentiment analysis? How does it work?

detecting favorable and unfavorable opinions toward specific products and services using numerous data sources

Predictive analytics

forecast of what may happen in the future, what could happen in the future based on the past?

Prescriptive analytics

helps facilitate decision-making, what should a business do?

What are the uses of forecasting? Give an example.

predict future events such as weather or confidence interval

How is analytics related to Big Data? How is it different?

related - they both mine useful information from data different - data analysts have a specific goal in mind and sort through relevant data