# Search results

1. ### Ensuring correct model specification

I would think that you would be at high risk for self-selection bias.
2. ### Help requested for 2-way ANOVA results interpretation

Answer 1) The rows p-value compares the mean effect of the control vs experiment while the interaction compares the slopes. Answer 2) It is better than the Mann-Whitney because it helps guard against the false positives of that many tests. You could also try a polynomial or nonlinear regression...
3. ### right-skewed distributed variable in regression model

Have you checked for multicollinearity? Plot all of your IVs by year. I suspect that you may find that some of them changed during the last four years. Unless your DV is affected by aging, time is usually a surrogate for other changes and would cause a multicollinearity problem.
4. ### Ppk, Cpk, or something else?

Welcome @gnojham . I see from your post that at least this particular thread is quality related. While this forum is statistics related, you will find few members that are fluent in quality topics. You will find more responses at the two quality forums below: Elsmar Cove Quality Forum Online...
5. ### confusion on outliers

There are a number of statistical tests for outliers, but do not rush to discard outliers. They raise the following questions: Is the measurement process stable? Is the distribution or model wrong? Is some transformation required? Is there an identifiable subset of observations that is...
6. ### Statistical analysis in agriculture and agronomy

It is really a general linear model.
7. ### Using Chi Square Test to check the effect of a variable?

Yes, you can use the chi-square test for this. The only caution I would give is that if your sample size gets too large, it can give false positive results.
8. ### Statistical analysis in agriculture and agronomy

I beg to differ on your description of ANCOVA. ANOVA with more than one predictor is k-way ANOVA. ANCOVA is a k-way ANOVA with a continuous covariate. ANOVA assumes that the factors are discrete, or if continuous, are studied at discrete levels, while the covariate may vary in a continuous...
9. ### Difference between rounding up and off a decimal?

There is a USA standard for rounding called ASTM E29 as well as an NCES standard 5-3. There is also an international standard IEEE 754.
10. ### Statistical test or method to analyse a change in a variable over time.

You are correct. I wasn't certain how your data were collected. You can use a 1-way ANOVA to determine whether any changes among the three groups are significant.
11. ### Statistical test or method to analyse a change in a variable over time.

One simple approach that you can try is to plot the time series (# people using food bank) on an individuals control chart. This is a technique developed in industrial statistics to determine whether a process is stable and predictable, or under the influence of outside causes. If your data...
12. ### How to do data analysis for Likert scale questions?

I agree with you Greta. I periodically analyze survey data with sample sizes in the thousands. Two questions may have distributions that are very different visually, yet have the same median and mode while the mean reflects the visual differences. While the mean may be somewhat biased in the...
13. ### Minitab 17 Discrete X Discrete Y Question

As previously stated, your model is fully saturated. There are only enough degrees of freedom to estimate 15 terms. Your main effects and all 2-way interactions total 15. You need at least one degree of freedom to estimate the error term for a significance test. The best way of doing that is...
14. ### Need help with the appropriate statistical method

A 2 proportions test.
15. ### Three-way ANOVA?

This does change it somewhat. It now appears to be a split plot repeated measures design. The whole plot is the starting level of nematode and has 5 replicates. The subplot is the cover crop/control and has 3 replicates. The repeated measures are the 4 times in which the nematode population...
16. ### Three-way ANOVA?

This is a split plot design (first developed in agriculture!). The field locations form the whole plots and the treatment/control form the subplots. Counting the population 4 times are repeats.
17. ### Correlation

What about using a cross correlation to determine whether one or more of the time series is a leading indicator for another?
18. ### Relationships change, why

Satisfaction is situational and will inherently change. If you have not read about the Kano model, I highly recommend doing so. I won't go through everything in the article, but want to point out the following: People will typically express satisfaction/dissatisfaction only about performance...
19. ### Finding Correlations

I performed the analysis in Minitab. Excel does not have the capability to perform a cluster analysis. You can generate the scatter plot in Excel using a scatter (X-Y) plot (see attached), but would need the output from other software.
20. ### Finding Correlations

Sorry. I did not attach the correct (latest) file. Here it is. And your interpretation of the responses vs cluster membership is correct.