Green Belt Certification Exam

How is variance calculated?

A P-chart might be used to display the rate of defectives for this type of capability analysis?

If extreme outliers exist in a dataset, this would warrant the use of __________ to illustrate the center location.

If the correlation coefficient of two variables is zero, the two variables are independent?

Correlation implies causation?

R2 measures the proportion of variability in the data which can be explained by the model?

In a multiple linear regression analysis, the p-values of the insignificant predictors are the ones that are smaller than the alpha level?

When eliminating insignificant variables from a multiple linear regression model, we should remove all insignificant variables at the same time?

Multicollinearity is the situation when two or more independent variables in a multiple regression model are correlated with each other?

Replication in DOE increases the total degrees of freedom?

Which of the following situations does NOT indicate that the simple linear regression model is statistically significant?

What is the total degrees of freedom of a simple linear regression model built using 25 data points?

Which of the following assumptions is NOT required to ensure the reliability of the linear regression model?

Pearson’s correlation coefficient measures both linear and non-linear relationship between two variables?

A correlation coefficient of 0.00 means there is absolutely no relationship?

Which of the following correlation coefficients best represents a strong positive linear relationship?

Which of the following correlation coefficients best represents a strong inverse linear relationship?

Which of the following correlation coefficients best represents a moderate positive linear relationship?

Which of the following correlation coefficients best represents the absence of a linear relationship?

Which of the following correlation coefficients do not represent a perfect linear relationship?

Which of the following is a way in which you might deal with multicollinearity?

Would increasing the sample size be an effective way to deal multicollinearity?

If VIF ≥ 10, there is no multicollinearity?

If VIF = 1, there is no multicollinearity?

R2 is also referred to as the coefficient of determination?

_________ is used to model the linear relationship between one output and two or more inputs?

_______ are the vertical differences between actual values and the predicted values or the “fitted line” created by a regression model?

When the variance inflation factor of an independent variable is larger than ______ there is large multicollinearity for this variable in the model?

What is the primary purpose of linear correlation analysis?

Multiple linear regression is best described by which?

What is the coefficient in this regression formula: Length = 3.5 + 1.29 mass

Regression analysis does not rely on this assumption about the residuals

When are correlation and linear regression not used?

Which of the following statements is NOT correct?

When is the degree of association Moderate?

What does a variance inflation factor (VIF) of 5 indicate?

Your multiple regression model returned 3 variables that were significant, and the model looks good based on all other measures. Of the 3 variables, which one has the most influence on your “Y?

Which of the following items should not be on control charts?

Which control chart should be used to track average defects per unit?

Which control chart should be used to track percent defective?

Which control chart should be used to track the count of defectives?

What is the recommended subgroup size when using Xbar-S chart to check for process stability?

What is the subgroup size when using a I-MR control chart?

The individuals chart in an IMR control chart is valid only if the moving range chart is in control?

Control charts are valid only if the data are normally distributed?

If a process is stable, the future performance of that process is predictable within certain limits?

In an EWMA chart, the more recent data gets more weight than the older data?

The subgroup sizes of an NP chart are constant?

Control limits are approximately _____ standard deviations away from the process mean?

The underlying distribution of the P chart is the _____ distribution?

SPC is used to identify the ____ cause variation?

You can use an individuals chart to track process outputs and to detect the presence of special causes using a sample size of 1?

The Xbar chart plots the average values of each of several small sampled subgroups

Which is incorrect about U-charts?

The NP and P-charts are used for tracking _________?

Control charts and their limits are the?

An intended outcome of using SPC should be?

SPC on the outputs is more preferred than SPC on the inputs when implementing SPC for your process.

Variation in process performance is a consequence of several causes that typically fall into which frequently used categories of variation?

for a good control chart implementation, you should re-calculate control limits and center-lines often?

The data on SPC charts are typically constructed such that the most recent data point is the last one on the right?

Which statement describes an undesirable situation when implementing SPC?

Which pair of control charts is most preferred for subgroup sizes of 10 or less using continuous data?

A t-test is a hypothesis test in which the test statistic follows the Student’s t distribution if the null hypothesis is true?

In which condition should you fail to reject the null hypothesis?

Inferential statistics is descriptive only and does not make any generalizations beyond the data at hand?

Which hypothesis test would be the most appropriate to compare the means of 2 samples

Which hypothesis test would be the most appropriate to compare the mean of a sample to a target value

Which hypothesis test would be the most appropriate to compare the median of 2 samples

One sample t-test is a hypothesis test to study whether there is a statistically significant difference between a population mean and a specified value or target?

One-tailed hypothesis test is used when we care about whether there is a difference between groups and we don’t care about the direction of the difference?

One-way ANOVA (one-way analysis of variance) is a statistical method to compare means of two or more populations?

One-way ANOVA (one-way analysis of variance) is a statistical method to compare variances of two or more populations?

Which of the following would not be considered an example of graphical analysis?

The Exponential distribution is very similar to the Poisson distribution except that the Exponential is built on continuous variables and the Poisson is built on discrete variables.

The higher the confidence level, the wider the confidence interval?

The more variability, the wider the confidence interval?

The null hypothesis for a normality test is that the data are normally distributed?

The null hypothesis for a Paired t-test is: MuA – MuB = 0

The proportion of the area under the sampling distribution and beyond the test statistic is p-value?

To reduce β risk, we decrease the sample size?

Which hypothesis test is used to check whether the population of our interest is normally distributed?

Which is NOT an assumption of a one-way ANOVA?

Which of the following is NOT a goal of rational subgrouping?

Which of the following tests would you use to determine if there is a statistically significant difference between a population mean and a specified value?

Which of these would you reject the null hypothesis?

α risk is the risk of making a Type I error?

Mann-Whitney test is a statistical hypothesis test to compare the _______of two populations which are not normally distributed?

When the p-value is _____ than the α level, we reject the null and claim that there is a statistically significant difference between different groups?

A _________ test is a statistical method in which a specific hypothesis is formulated about the population, and the decision of whether to reject the hypothesis is made based on sample data?

A population is grouped into distinct and independent categories and then samples are randomly or systematically selected in each category of the population. Which sampling strategy is it?

Statistical inference is the process of making inferences regarding the characteristics of an unobservable population based on the characteristics of the observed sample?

The process of selecting a subset of observations within a population is referred to as sampling?

_________ is applied to infer the characteristics or relationships of the populations from which the data are collected?

If the p-value is less than 0.05 what is the general rule?

Which is not indicative of statistical inference

The population used in statistics is defined as a sample large enough that you can analyze it and draw conclusions as to all the data?

Hypothesis testing can help establish a statistical difference among factors in data sets?

A two-sample T-test does which of the following?

Which of the following is TRUE about Type I and Type II errors?

What are confidence intervals (CI)?

The Central Limit Theorem says that…

What test is used with an attribute Y and 3 X’s?

What test should be used when comparing the average height of people from 2 different countries?

Which test should be used to compare the average results of 7 different Green Belt classes?

When is the F-test NOT used?

Hypothesis testing can help us…

A department has a hypothesis that its sales average is $17,200 per month. A sample report of 11 months shows a mean of $16,221. The standard deviation is $3,996. Using an alpha level of 5% and degrees of freedom (DF), what is the critical-T value for a 2-sided test as required in this case:

If a hypothesis test shows a p-value of 0.28, but we see a practical difference, what could be a reason for failing to reject the null when there may be a difference?

Every hypothesis test must have the following except?

The Mann-Whitney test focuses on what?

Which tool is used to compare more than two sample proportions with each other?