Exam 1

Question 1

What is Predictive Analytics? (3)

Answer 1

• analyze past performance
• extrapolates to future
• predicts risks

Question 2

What is the difference between Mean and Median?

Answer 2

Mean is affected by outliers while Median is not

Question 3

What is a sample point?

Answer 3

The most basic outcome of an experiment

Question 4

What is Descriptive Analytics? (3)

Answer 4

• uses data to understand past and present
• summarizes data into meaningful charts and reports
• identify patterns and trends in data

Question 5

What is Prescriptive analytics? (2)

Answer 5

• uses optimization techniques to identify best alternatives
• often combined with predictive analytics to account for risk

Question 6

Chebyshev’s Theorem Equation

Answer 6

1 - 1/k^2

Question 7

What is the purpose of sampling?

Answer 7

we cannot get all the data, all the time, in the real world we get only a small portion of the data

Question 8

What is the mean?

Answer 8

The average value of a data set

Question 9

What is the median?

Answer 9

Find the middle number in a data set

Question 10

What is covariance?

Answer 10

used to determine how much two random variables go together

Question 11

What is correlation?

Answer 11

used to determine when a change in one variable can result in a change in another

Question 12

What do correlation and covariance have in common?

Answer 12

they both measure linear relationships between variables

Question 13

What are the two sampling methods?

Answer 13

Subjective Methods and Probability Sampling

Question 14

What are the two types of subjective methods for sampling?

Answer 14

judgment sampling and convenience sampling

Question 15

Judgement Sampling

Answer 15

Expert Judgement is used

Question 16

Convenience Sampling

Answer 16

Collect sample based on convenience

Question 17

4 Types of Statistical Sampling

Answer 17

1) Systematic (periodic) sampling
2) Stratified Sampling
3) Cluster Sampling
4) Sampling from a continuous process

Question 18

Systematic (Periodic) sampling

Answer 18

selects every nth item from a population

Question 19

Stratified Sampling

Answer 19

population divided into subsets and allocates specific proportion of samples to each subset

Question 20

Cluster Sampling

Answer 20

divide the population into clusters and sample a set of clusters

Question 21

Sampling from a continuous process

Answer 21

• fix the time and select n items after that time or selected next item after each

Question 22

What is a sampling error?

Answer 22

a statistical error that occurs due to the sample not being well represented

Question 23

T/F: a good example of independent events are rolling a dice or flipping a coin

Answer 23

TRUE

Question 24

What does a union look like and what does it do?

Answer 24

• looks like a “U”
• OR statement

Question 25

What does an intersection look like and what does it do?

Answer 25

- looks like an "n" - AND statement

Question 26

Type I error is a

Answer 26

false positive incorrectly reject H0 (person put in jail that is innocent)

Question 27

Type II error is...

Answer 27

false negative incorrectly fails to reject H0 (person found not guilty when actually guilty)

Question 28

How do you write a null hypothesis?

Answer 28

you hypothesize that no change will occur

Question 29

if the p-value is less than alpha you...

Answer 29

reject the null

Question 30

if the p-value is greater than or equal to alpha you...

Answer 30

fail to reject the null

Question 31

the probability of obtaining results as extreme as the observed results of a statistical test is...

Answer 31

the p-value

Question 32

the significance level (set by the researcher or stated) is...

Answer 32

alpha

Question 33

The maximum number of logically independent values, which are values that have the freedom to vary, in the sample data is...

Answer 33

df (degrees of freedom) (N columns - 1) * (N rows - 1)

Question 34

Hypothesis testing is done under the assumption the null hypothesis is...

Answer 34

TRUE

Question 35

p-value written as probability statement

Answer 35

P(sample s | H0 True)

Question 36

Four types of data based on measurement scale

Answer 36

- Categorical (Nominal) - Ordinal - Interval - Ratio

Question 37

Two Types of Categorical Data

Answer 37

- Nominal - Ordinal

Question 38

Two types of numerical data

Answer 38

- Interval - Ratio

Question 39

What is Categorical (nominal) data?

Answer 39

data placed in categories according to a specified characteristic ex: product types, storage locations, gender

Question 40

What is Ordinal Data?

Answer 40

Data that is ranked or ordered according to some relationship with one another ex: customer satisfaction levels, risk levels, t-shirt size

Question 41

What is Interval Data?

Answer 41

Ordinal data but with constant differences between observations & has NO TRUE ZERO POINT ex: PH scale, time on a 12 hour clock

Question 42

What is Ratio Data?

Answer 42

continuous values and have natural zero point ex: monthly sales, height, weight, time spent