Descriptive Statistics

Question 1

Statistics

Answer 1

both the science of uncertainty and the technology of extracting information from data
- involves collecting, organizing, analyzing, interpreting, and presenting data
- a summary measure of data

Question 2

Descriptive Statistics

Answer 2

methods of describing and summarizing data using tabular, visual, and quantitative techniques

Question 3

Discrete Metrics

Answer 3

derived from counting something
- a delivery is on time or not
- not infinite possibilities

Question 4

Continuous Metrics

Answer 4

based on a continuous scale of measurement
- involving dollars, length, time, volume, or weight
- ex: 1.1 hours of time

Question 5

Frequency Distribution

Answer 5

a table that shows the number of observations in each of several non-overlapping groups

Question 6

What is a graphical depiction of a frequency distribution?

Answer 6

histogram

Question 7

Frequency Distributions for Categorical Data

Answer 7

categorical variables naturally define the groups in a frequency distribution (histograms)

Question 8

Population

Answer 8

ALL items of interest
- all subscribers to Netflix

Question 9

Sample

Answer 9

A subset of the population
- a list of people who watched a true crime on Netflix in past year
- cheaper, quicker, availability

Question 10

Averages

Answer 10

X̅

Question 11

N=

Answer 11

population number of items

Question 12

n=

Answer 12

sample number of items/observations

Question 12

Median

Answer 12

middle value when data are arranged from least to greatest

Question 13

Mode

Answer 13

observation that occurs most frequently

Question 14

Measures of Dispersion

Answer 14

degree of variation in the data
- numerical spread of the data

Question 15

Range

Answer 15

the difference between the maximum and minimum value in the data set
- affected by outliers

Question 16

Variance

Answer 16

a statistical measurement of the spread between numbers in a data set
- average of squared deviations of the mean

Question 17

Standard Deviation

Answer 17

square root of the variance

Question 18

Empirical rules 68

Answer 18

Approx 68% fall within one standard deviation of the mean u-o, u+o

Question 19

Empirical rules 95

Answer 19

Approx 95% fall within two standard deviations u-2o, u+2o

Question 20

Empirical rules 99.7

Answer 20

Approx 98% fall within three standard deviations u-3o, u+3o

Question 21

Measures of Association

Answer 21

Two variables have a strong statistical relationship with one another if they move together

Question 22

When two variables appear to be related=

Answer 22

cause-and-effect relationship

Question 23

Covariance

Answer 23

a measure of the DIRECTION of the linear relationship between two variables, X and Y

Question 24

The covariance between X and Y is the average of the product of the deviations

Answer 24

of each pair of observations from their respective means

Question 25

Correlation

Answer 25

is a measure of the STRENGTH and DIRECTION of the linear relationship between two variables, X and Y

Question 26

Statistical Thinking

Answer 26

philosophy of learning based on:
- all work occurs in a system of interconnected processes
- variation exists in all processes