Here is a question I received from a student by e-mail.

“Could you clraify exactly what it means to estimate the level of confidence of our conclusion. What is our conclusion on (which part of the guide) and how are we to estimate the level of confidence of the conclusion if it is a written statement.”

My answer:

“You are trying to answer the question:

‘Is there a significant difference between the number of counts/minute detected when the nu-salt is present compared to when the nu-salt was not present?’

You need to use the statistical quantities we measured for the number of counts/minute both with and without the nu-salt present: average, standard deviation, number of counts and standard deviation of the mean. The level of confidence will depend on how far apart the averages of the two experiments are compared to the standard deviations of the means.”

In other words, if the means differ by about 1 SDM then you can conclude that the difference is real to a 68% level of confidence. If they differ by 2 SDM then they differ to a 95% level of confidence. If they differ by something between 1 SDM and 2 SDM then you conclude that the difference is real to something between 68% and 95% level of confidence.