Posts by Michael Parker
Scatter Plot with JMP
What is a Scatter Plot? A scatter plot is a diagram to present the relationship between two variables of a data set. A scatterplot consists of a set of data points. On the scatterplot, a single observation is presented by a data point with its horizontal position equal to the value of one variable and…
Read MoreMann Whitney Testing with JMP
What is the Mann Whitney Test? The Mann Whitney test (also called Mann–Whitney U test or Wilcoxon rank-sum test) is a statistical hypothesis test to compare the medians of two populations that are not normally distributed. In a non-normal distribution, the median is the better representation of the center of the distribution. Null Hypothesis (H0): η1…
Read MoreXbar S Chart with SigmaXL
What is a Xbar S Chart? The X-S chart (also called Xbar S chart) is a control chart for continuous data with a constant subgroup size greater than ten. The Xbar chart plots the average of a subgroup as a data point. The S chart plots the standard deviation within a subgroup as a data…
Read MoreXbar S Chart with JMP
What is a Xbar S Chart? The X-S chart (also called Xbar S chart) is a control chart for continuous data with a constant subgroup size greater than ten. The Xbar chart plots the average of a subgroup as a data point. The S chart plots the standard deviation within a subgroup as a data…
Read MoreXbar S Chart with Minitab
What is a Xbar S Chart? The X-S chart (also called Xbar S chart) is a control chart for continuous data with a constant subgroup size greater than ten. The Xbar chart plots the average of a subgroup as a data point. The S chart plots the standard deviation within a subgroup as a data…
Read MoreNP Chart with SigmaXL
What is an NP Chart? The NP chart is a control chart monitoring the count of defectives. It plots the number of defectives in one subgroup as a data point. The subgroup size of the NP-chart is constant. The underlying distribution of this control chart is binomial distribution. NP Chart Equations NP-chart Data Point: Center…
Read MoreNP Chart with JMP
What is NP Chart? The NP chart is a control chart monitoring the count of defectives. It plots the number of defectives in one subgroup as a data point. The subgroup size of the NP-chart is constant. The underlying distribution of this control chart is binomial distribution. NP Chart Equations NP-chart Data Point: Center Line:…
Read MoreNP Chart with Minitab
What is a NP Chart? The NP chart is a control chart monitoring the count of defectives. It plots the number of defectives in one subgroup as a data point. The subgroup size of the NP-chart is constant. The underlying distribution of this control chart is binomial distribution. NP Chart Equations NP-chart Data Point: Center…
Read MoreCumSum Chart with JMP
What is a CumSum Chart? The CumSum chart (also called cumulative sum control chart or CUMSUM chart) is a control chart of monitoring the cumulative sum of the subgroup mean deviations from the process target. It detects the shift of the process mean from the process target over time. The underlying distribution of the CumSum…
Read MoreCumSum Chart with Minitab
What is a CumSum Chart? The CumSum chart (also called cumulative sum control chart or CUSUM chart) is a control chart of monitoring the cumulative sum of the subgroup mean deviations from the process target. It detects the shift of the process mean from the process target over time. The underlying distribution of the CuSum…
Read MoreEWMA Chart with JMP
What is EWMA Chart? The EWMA chart (Exponentially-Weighted Moving Average Chart) is a control chart monitoring the exponentially-weighted average of previous and present subgroup means. The more recent data get more weight than older data. It detects the shift of the process mean from the process target over time. The underlying distribution of the EWMA…
Read MoreEWMA Chart with Minitab
What is an EWMA Chart? The EWMA chart (Exponentially-Weighted Moving Average Chart) is a control chart monitoring the exponentially-weighted average of previous and present subgroup means. The more recent data get more weight than older data. It detects the shift of the process mean from the process target over time. The underlying distribution of the…
Read MoreKruskal Wallis Test with Minitab
Kruskal Wallis One-Way Analysis of Variance The Kruskal Wallis one-way analysis of variance is a statistical hypothesis test to compare the medians among more than two groups. Null Hypothesis (H0): η1 = η2 = … = ηk Alternative Hypothesis (Ha): at least one of the medians is different from others Where: ηi is the median…
Read MoreOne Sample Wilcoxon Test with Minitab
What is the One Sample Wilcoxon Test? The one sample Wilcoxon test is a hypothesis test to compare the median of one population with a specified value. Null Hypothesis (H0): η = η0 Alternative Hypothesis (Ha): η ≠ η0 It is an alternative test of one sample t-test when the distribution of the data is non-normal. It is…
Read MoreOne Sample Proportion Test with Minitab
What is the One Sample Proportion Test? One sample proportion test is a hypothesis test to compare the proportion of one certain outcome (e.g. the number of successes per the number of trials, or the number of defects per the total number of opportunities) occurring in a population following the binomial distribution with a specified…
Read MoreMedian Test with Minitab
What is Mood’s Median Test? Mood’s median test is a statistical test to compare the medians of two or more populations. Null Hypothesis (H0): η1 = … = ηk Alternative Hypothesis (Ha): At least one of the medians is different from the others The symbol k is the number of groups of our interest and…
Read MoreMann Whitney Testing with Minitab
What is the Mann Whitney Test? The Mann Whitney test (also called Mann–Whitney U test or Wilcoxon rank-sum test) is a statistical hypothesis test to compare the medians of two populations that are not normally distributed. In a non-normal distribution, the median is the better representation of the center of the distribution. Null Hypothesis (H0): η1…
Read MoreOne Way ANOVA with Minitab
What is One Way ANOVA? One way ANOVA is a statistical method to compare means of two or more populations. Null Hypothesis(H0): Alternative Hypothesis(Ha): At least one μi is different, where i is any value from 1 to k It is a generalized form of the two sample t-test since a two sample t-test compares…
Read MorePaired t Test with Minitab
What is a Paired t Test? A Third type of a Two Sample t-Test is the Paired t Test. This test is used when the two populations are dependent of each other, so each data point from one distribution corresponds to a data point in the other distribution. When using a paired t test, the…
Read MoreTwo Sample t Test with Minitab
What is Two Sample T Test? Two sample t test is a hypothesis test to study whether there is a statistically significant difference between the means of two populations. Null Hypothesis (H0): μ1 = μ2 Alternative Hypothesis Ha) : μ1 ≠ μ2 Where: μ1 is the mean of one population and μ2 is the mean of…
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