A pharmaceutical company producing a COVID vaccine wants to know how long post-injection side effects last. They hire a researched to study this. The researcher draws a sample of 100 and finds a mean duration of symptoms of 16 hours with a standard deviation of 5. Which of the following is an accurate interpretation, based on your calculated 95% confidence intervals? The true population mean less than 100 . The estimated population mean is precisely 100. We can be 95% certainty that the true population mean lies within our 95% confidence interval. Its impossible to estimate the population mean.