Hi everyone,
I've been asked to take a new direction with one of the research questions in my dissertation fairly last minute so I'd be really grateful of your help. I'm looking at the pH values from two treatment groups and my hypothesis is:
H1: The heat samples have a significantly more acidic postexposure pH in comparison to the nutrient samples.
The data don't fully meet assumptions for parametric tests (see attached screenshot with Shapiro Wilk, Skewness & Kurtosis results). I used Wilcoxon rank sum to test for a statistically significant difference between the groups and was able to reject the null, but I assume I can't use those results to answer the above hypothesis?
Here is the write up from the Wilcoxon rank sum test:
"Data for pH did not meet assumptions of normality for an independent samples Ttest (see Table X), so the Wilcoxon Rank Sum test was used. The median pH in the heat treatment was 6.16 (IQR = .37), whereas the median in the nutrients treatment was 7.34 (IQR = 1.01) as seen in Figure X. The Wilcoxon Rank Sum test revealed that the difference the location of the medians was significantly different (95% conf interval, W = 16, p = <.001, effect size r = 0.83)."
Thanks in advance,
Stay safe all
I've been asked to take a new direction with one of the research questions in my dissertation fairly last minute so I'd be really grateful of your help. I'm looking at the pH values from two treatment groups and my hypothesis is:
H1: The heat samples have a significantly more acidic postexposure pH in comparison to the nutrient samples.
The data don't fully meet assumptions for parametric tests (see attached screenshot with Shapiro Wilk, Skewness & Kurtosis results). I used Wilcoxon rank sum to test for a statistically significant difference between the groups and was able to reject the null, but I assume I can't use those results to answer the above hypothesis?
Here is the write up from the Wilcoxon rank sum test:
"Data for pH did not meet assumptions of normality for an independent samples Ttest (see Table X), so the Wilcoxon Rank Sum test was used. The median pH in the heat treatment was 6.16 (IQR = .37), whereas the median in the nutrients treatment was 7.34 (IQR = 1.01) as seen in Figure X. The Wilcoxon Rank Sum test revealed that the difference the location of the medians was significantly different (95% conf interval, W = 16, p = <.001, effect size r = 0.83)."
Thanks in advance,
Stay safe all
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