Black Belt Test Review Flashcards
1
Q
What is the abbreviation for DMAIC
A
Define, Measure, Analyze, Improve, Control
2
Q
Six sigma primary emphasis is…
A
Reducing variation and defects
3
Q
What are the 4 Types of Control
A
- Training, work instructions, audits
- Control charts for the outputs
- Control charts for the inputs
- Error proofing is the best
4
Q
Project charter should consist of these 3 things…
A
- The project plan
- Should be flexible
- Serves as the record of the project
5
Q
2 types of Statistics
A
Descriptive and Inferential
6
Q
Descriptive statistics
A
Central tendency measures are used to indicate where most of the data points gather (mean, mode, median)
Variation measures are used to indicate degree of dispersion (range, variance, standard deviation)
7
Q
Measures of Central Tendency
A
- Mean (aka X Bar, average of data)
- Median (middle value)
- Mode (most frequent)
8
Q
Measures of Variation
A
- Standard deviation - average distance any point is from mean of data set (aka Sigma)
- Range - difference between the max and min data values of data set
R = Max - Min
9
Q
What is Normal Distribution
A
Data will tend to follow a normal distribution
Also known as bell curve
There is a finite mean and data points around the mean
The mean, median, and mode are approx equal
10
Q
What is the Anderson Darling Normality Test (A-D Test)
A
Statistical method used to assess whether a given sample of data follows a specific distribution
11
Q
Types of Data
A
- Variable (Continuous) - Quantitative data, anything you can measure some scale ex: weight, length, time
- Attribute (discrete) - Qualitative data (pass/fail, color)
12
Q
Hypothesis test
A
A method of statistical inference used to decide whether the data provide sufficient evidence to reject a particular hypothesis
13
Q
What tests do we use for attribute (discrete) data?
A
- 1-Proportion test
- 2-Proportion test
- Chi-Square test
14
Q
What tests do we use for variable (continuous) data?
A
- T test (1 or 2 sample)
- Paired T test
- Test for Equal Variances
- ANOVA
- Correlation
- F Test / Levenes
15
Q
In a hypothesis test, what do we use to test some theory about our process?
A
The null hypothesis
16
Q
The null hypothesis will…
A
- Always have stats we are interested in
- Make a claim about population
- Always have a statement of equality ( an “=”)
- Not always be what we think
17
Q
What do we use to test against the null hypothesis?
A
Alternate hypothesis
18
Q
The alternate hypothesis will…
A
- Involve the same statistic as the null hypothesis
- Opposite of the null ( does not equal)
- Offer the only possible alternative
19
Q
When do we reject the null?
A
We have gathered enough evidence / the truth is something other than the null
20
Q
When do we fail to reject the null?
A
We have not gathered enough evidence to say that the null is false
21
Q
What is the alpha risk?
A
Quantified reasonable doubt
22
Q
What percent do we use of alpha risk?
A
5%
23
Q
If the P-Value is less than 5%, do we reject or accept?
A
Reject
24
Q
If the P is low____
A
The null must go!
25
If the P is high ____
The null is your guy!
26
Alpha Risk / Type 1 Error
Rejected the null, but the null was true
27
Beta Risk / Type 2 Error
Failed to reject the null, but the null was false
28
In hypothesis tests, what is the Resolution (difference)
The difference that the test is able to detect
29
In hypothesis tests, what % do we want our experiments to achieve?
At least 80%
30
What is 1-Proportion Testing?
Tool to compare a single set of attribute sample data to some fixed value
31
What is 2-Proportion Testing?
Tool to compare a 2 sets of attribute sample data to some fixed value (two sample testing)
32
If the p-value is below our alpha risk level of 0.05, do we reject or does it fail to reject the null?
Reject the null
33
Does the following pass the hypothesis test?
No, we reject the null because the P value 0.004 < 0.05
34
What test do we use to compare standard deviation of different samples?
Test for equal variances
35
What is the 1-sample t-test?
A test where we compare our sample mean with some hypothesized population mean
36
What is the first step in a t-test, after we have gathered a data set that we want to try?
Test for normality
37
What is the second step in a t-test, after we have gathered a data set that we want to try?
Check for stability (control charts)
38
What is the T-value and P value in the following 2-sample t-test diagram?
t-value: 2.63
p-value: 0.014
39
What does ANOVA stand for?
Analysis of variance
40
What test do we use if we have more than 2 samples that we want to test?
ANOVA
41
What does ANOVA compare?
Compares the variances of the different samples to derive conclusions about the means of those samples
42
True or False - ANOVA assumes that the variances are statistically equal
True
43
Use the P-value to either:
1. Reject the null
2. Fail to reject the null
44
P-values
Probability of observing this sample if the null hypothesis is true
45
True or False: If the P-value is less than 5%, we reject the null hypothesis
True
46
True or false: Larger sample sizes are good
True
47
True or false: We are looking for 80% power, which is equal to 20% risk
True
48
Hypothesis Testing Steps
1. Select hypothesis test
2. State null and alternate hypothesis
3. Determine power and sample size, select alpha risk
4. Collect samples
5. Perform the hypothesis test
6. Compare-value to the alpha risk (reject null or fail to reject null)
49
Correlation analysis
When we are dealing with two variable measures and want to determine if there is a relationship between them (ex: wind speed and electric current from a windmill)
50
In correlation analysis, what is the first of the two numbers called?
Correlation coefficient
51
If the correlation coefficient is equal to +1....
Perfectly positively correlated
52
If the correlation coefficient is equal to -1....
Perfectly negatively correlated
53
If the correlation coefficient is equal to zero...
No relationship between the two variables
54
What is regression?
Analyzes the relationship between a series of ordered pairs (x, y)
55
Regression equations
56
What does DOE stand for?
Design of Experiments
57
What is the benefit of DOE?
You can focus on many inputs and can be evaluated at the same time
58
Types of DOEs
Full factorial
Fractional
Mixture
Taguchi
Response surface analysis
EVOP (evolutionary operations)
59
What does FMEA stand for?
Failure Mode and Effects Analysis
60
What are the two types of FMEAs?
Process (PFMEA) and Design (DFMEA)
61
What is a Gate Review?
Reviews to ensure that prior work was completed successfully and the project is ready to proceed to the next major phase
62
Kill-Cure-Continue (In Gate Reviews)
Kill - Stop the project
Cure - Get resources needed
Continue - Continue with the project work
63
What does DMAIC stand for?
· A) Define, Measure, Analyze, Improve, Control
· B) Define, Monitor, Act, Improve, Control
· C) Determine, Measure, Act, Investigate, Control
· D) Define, Monitor, Act, Investigate, Correct
A) Define, Measure, Analyze, Improve, Control
64
Which of the following is a key goal of the "Define" phase in DMAIC?
A) To identify potential causes of the problem
· B) To gather data about the process
· C) To understand the problem and set project goals
· D) To implement solutions to the problem
C) To understand the problem and set project goals
65
Which tool is commonly used to analyze the root causes of a problem?
A) Histogram
· B) Fishbone diagram
· C) Control chart
· D) Pareto chart
B) Fishbone diagram
66
What does a "P-value" of less than 0.05 indicate in hypothesis testing?
· A) The null hypothesis is likely true
· B) The results are statistically significant
· C) There is no difference between groups
· D) The sample size is too small
B) The results are statistically significant
67
In the "Measure" phase, what is the primary objective?
· A) Implementing process changes
· B) Collecting data and assessing process performance
· C) Analyzing root causes
· D) Setting long-term goals for the project
B) Collecting data and assessing process performance
68
Which of the following is a common form of waste in Lean thinking?
· A) Overproduction
· B) Waste reduction
· C) Increased lead time
· D) Increased process variability
A) Overproduction
69
Which statistical test would you use to compare the means of two groups?
· A) Chi-square test
· B) T-test
· C) ANOVA
· D) Regression analysis
B) T-test
70
What is the purpose of a control chart?
· A) To compare two variables
· B) To monitor process stability over time
· C) To find the root cause of defects
· D) To show the relationship between input and output
B) To monitor process stability over time
71
What is a key characteristic of the "Improve" phase of DMAIC?
· A) Designing solutions based on the root causes
· B) Monitoring process performance
· C) Identifying potential risks
· D) Setting baseline measurements
A) Designing solutions based on the root causes
72
What is the main objective of the "Control" phase in DMAIC?
· A) To collect data on the current process
· B) To implement changes to improve the process
· C) To sustain improvements and monitor the process
· D) To analyze potential causes of defects
C) To sustain improvements and monitor the process
73
In hypothesis testing, the null hypothesis (H₀) is typically:
· A) A statement that there is no effect or no difference
· B) A statement that there is a significant effect or difference
· C) A statement that both groups are equal
· D) The same as the alternative hypothesis (H₁)
A) A statement that there is no effect or no difference
74
If the p-value in a hypothesis test is less than the significance level (α), you should:
· A) Fail to reject the null hypothesis
· B) Reject the null hypothesis
· C) Accept the null hypothesis
· D) Change the sample size
B) Reject the null hypothesis
75
A two-tailed test in hypothesis testing is used to determine if:
· A) The mean is equal to a specific value
· B) The mean is either greater than or less than a specific value
· C) The mean is different from a specific value in both directions
· D) None of the above
C) The mean is different from a specific value in both directions
76
In hypothesis testing, a Type I error occurs when:
· A) You fail to reject the null hypothesis when it is false
· B) You reject the null hypothesis when it is true
· C) You reject the alternative hypothesis when it is false
· D) None of the above
B) You reject the null hypothesis when it is true
77
What is the purpose of the alternative hypothesis (H₁)?
· A) To assume the null hypothesis is correct
· B) To propose a relationship or effect that contradicts the null hypothesis
· C) To prove that the null hypothesis is true
· D) To confirm the data collected in the experiment
B) To propose a relationship or effect that contradicts the null hypothesis
78
Which test would you use to compare the means of two independent groups in hypothesis testing?
· A) Chi-square test
· B) T-test
· C) ANOVA
· D) Regression analysis
B) T-test
79
What is the significance level (α) in hypothesis testing?
· A) The probability of making a Type II error
· B) The probability of making a Type I error
· C) The probability of rejecting the alternative hypothesis
· D) The probability of accepting the null hypothesis
B) The probability of making a Type I error
80
In a hypothesis test, a p-value greater than the significance level (α) means:
· A) There is strong evidence to reject the null hypothesis
· B) There is weak evidence to reject the null hypothesis
· C) The alternative hypothesis is true
· D) The null hypothesis is proven to be true
B) There is weak evidence to reject the null hypothesis
81
The number of cars in a parking lot.
· A) Discrete
· B) Continuous
A) Discrete
82
The weight of a person.
· A) Discrete
· B) Continuous
B) Continuous
83
The number of students in a classroom.
· A) Discrete
· B) Continuous
A) Discrete
84
The temperature in a city at noon.
· A) Discrete
· B) Continuous
B) Continuous
85
The number of calls received by a customer service center in an hour.
· A) Discrete
· B) Continuous
A) Discrete
