Soluble sugar in plants, σ = 3
Firstly make the point that we are about 95% sure that the error from using any estimator will be less than 2SE. In the contest of estimating a popn mean, we are therefore 95% confident that µ is in the interval
The diagram shows a random sample (n = 16) and shows the calculations to find the 95% confidence interval.
Click Another sample and mention that the width of the interval is the same — it only depends on σ and n — but it is centred on the new sample mean.
Increase the sample size to show that the width of the CIs decrease.
Laboratory testing for soluble sugars in plants is not precise. One analysis gives glucose concentrations that are centred on the true concentration, µ mg/g dry weight.
X ~ normal (μ , σ = 3)