0
$\begingroup$

I have a quick question regarding which statistical test to use to test for a significant difference.

My set of data shows the monthly output of a product for the years between 2013-2017. A new system was put in place in mid-2017 to make the output process more efficient which has led to increased output.

I have calculated the mean output level (units) for each month 2013-2016 and want to compare this to the actual output in 2017.

Which statistical test can I use to show a significant difference for output in the months of June, July, Aug and Sept 2017 which have a higher output level compared to the 2013-2016 average?

enter image description here

enter image description here

Kind regards,

Harvey

$\endgroup$
  • $\begingroup$ Are you really interested in just testing for a statistically significant difference or a meaningful difference? Would it really be helpful if you found a 0.00001 difference and that was statistically significant? $\endgroup$ – StatsStudent Jan 6 at 20:15
  • $\begingroup$ Hi there, Thanks for the reply. I was hoping to find a significant difference (p<0.05). I was thinking perhaps a T-Test or an ANOVA test ? $\endgroup$ – Harvey Jan 6 at 20:32
  • $\begingroup$ Was the supposedly superior new process in place only during May-Aug? Or did it continue from May through the end of the year. // It seems you should make the comparison only for months in which the process was different. $\endgroup$ – BruceET Jan 6 at 20:37
  • $\begingroup$ Hi there, the process was introduced in May and continued after that. The process aimed to alleviate a backlog of output orders hence the spike. Which statistical test could I use to easily show a sig. difference? $\endgroup$ – Harvey Jan 6 at 20:47
  • $\begingroup$ Comment continued: With data ` old = c(20.25, 20.5, 24.25, 33.75); new = c(87, 48, 52, 44)` a one-sided paired t test in R using ` t.test(old, new, pair=T, alte="less")` returns P-value 3.5%. A one-sample Wilcoxon test on the four differences cannot show a P-value smaller than 5% because there aren't enough pairs. $\endgroup$ – BruceET Jan 6 at 20:47

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Browse other questions tagged or ask your own question.