 Hey there, this is a video on building a confidence interval for a population mean Ashley wants to determine the number of chocolate chips and cookies at her bakery She randomly selects a sample of 52 cookies and obtains a sample mean of 6.3 and standard deviation of 2.2 What is the 98% confidence interval for the number of chocolate chips per cookie? Round your answer to three decimal places We will use technology for this But the first thing we need to understand is our population standard deviation sigma Is not known which means We have to consider using the t distribution All this means is that we'll go to a different region to put our information in and google sheets Looking at the question, I know that there is a sample of 52 cookies. So n is equal to 52 I also know that in her sample the sample mean x bar was 6.3 And sample standard deviation s was 2.2 And the only other thing they give me is a confidence level of 98% or 0.98 This is the information we need to put in google sheets to find our confidence interval So we will travel to google sheets now and we will go to the data list tab Because we have summary statistics to put in We know the sample mean we know the sample standard deviation You will go to the one variable confidence level p value region that says t distribution In this case x bar was 6.3 Sample standard deviation 2.2 sample size 52 And the only other piece of information you need would be the confidence level 0.98 So this means that your lower limit will be 5.567 upper limit 7.033 That's rounded to three decimal places So what I know is that my population mean is between 7.033 and 5.567 You can also write this as an interval notation as 5.567 7.033 These are the two different ways you could write this confidence interval And what this is saying is that the true population mean The number of chocolate chips per cookie and all of the cookies in the bakery Will be somewhere between 5.567 and 7.033 So that's how you calculate a confidence interval Thanks for watching