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IDIS 450 > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

What is Predictive Analytics? (3)

A
  • analyze past performance
  • extrapolates to future
  • predicts risks
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2
Q

What is the difference between Mean and Median?

A

Mean is affected by outliers while Median is not

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3
Q

What is a sample point?

A

The most basic outcome of an experiment

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4
Q

What is Descriptive Analytics? (3)

A
  • uses data to understand past and present
  • summarizes data into meaningful charts and reports
  • identify patterns and trends in data
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5
Q

What is Prescriptive analytics? (2)

A
  • uses optimization techniques to identify best alternatives
  • often combined with predictive analytics to account for risk
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6
Q

Chebyshev’s Theorem Equation

A

1 - 1/k^2

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7
Q

What is the purpose of sampling?

A

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

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8
Q

What is the mean?

A

The average value of a data set

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9
Q

What is the median?

A

Find the middle number in a data set

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10
Q

What is covariance?

A

used to determine how much two random variables go together

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11
Q

What is correlation?

A

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

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12
Q

What do correlation and covariance have in common?

A

they both measure linear relationships between variables

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13
Q

What are the two sampling methods?

A

Subjective Methods and Probability Sampling

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14
Q

What are the two types of subjective methods for sampling?

A

judgment sampling and convenience sampling

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15
Q

Judgement Sampling

A

Expert Judgement is used

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16
Q

Convenience Sampling

A

Collect sample based on convenience

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17
Q

4 Types of Statistical Sampling

A

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

18
Q

Systematic (Periodic) sampling

A

selects every nth item from a population

19
Q

Stratified Sampling

A

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

20
Q

Cluster Sampling

A

divide the population into clusters and sample a set of clusters

21
Q

Sampling from a continuous process

A
  • fix the time and select n items after that time or selected next item after each
22
Q

What is a sampling error?

A

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

23
Q

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

A

TRUE

24
Q

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

A
  • looks like a “U”
  • OR statement
25
Q

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

A
  • looks like an “n”
  • AND statement
26
Q

Type I error is a

A

false positive

incorrectly reject H0

(person put in jail that is innocent)

27
Q

Type II error is…

A

false negative

incorrectly fails to reject H0

(person found not guilty when actually guilty)

28
Q

How do you write a null hypothesis?

A

you hypothesize that no change will occur

29
Q

if the p-value is less than alpha you…

A

reject the null

30
Q

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

A

fail to reject the null

31
Q

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

A

the p-value

32
Q

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

A

alpha

33
Q

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

A

df (degrees of freedom)

(N columns - 1) * (N rows - 1)

34
Q

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

A

TRUE

35
Q

p-value written as probability statement

A

P(sample s | H0 True)

36
Q

Four types of data based on measurement scale

A
  • Categorical (Nominal)
  • Ordinal
  • Interval
  • Ratio
37
Q

Two Types of Categorical Data

A
  • Nominal
  • Ordinal
38
Q

Two types of numerical data

A
  • Interval
  • Ratio
39
Q

What is Categorical (nominal) data?

A

data placed in categories according to a specified characteristic

ex: product types, storage locations, gender

40
Q

What is Ordinal Data?

A

Data that is ranked or ordered according to some relationship with one another

ex: customer satisfaction levels, risk levels, t-shirt size

41
Q

What is Interval Data?

A

Ordinal data but with constant differences between observations & has NO TRUE ZERO POINT

ex: PH scale, time on a 12 hour clock

42
Q

What is Ratio Data?

A

continuous values and have natural zero point

ex: monthly sales, height, weight, time spent

IDIS 450 (3 decks)

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