D Question 9 1 pts Go to artofstat.com, click on Web Apps, scroll down and open the Explore Coverage app. Change the tab at the top of the page to Confidence Interval for a Mean. Change the "Select shape of population distribution" drop down menu to Bell-shaped and use the default mean=50 and standard deviation=10. Under "Select sample size (n)" use the default of n=30 and under "Choose confidence level (in %)" use the default 95. Under "Select how many samples (of size n) you want to draw from the population" start with just 1. Click on "Draw sample(s)" and note that a confidence interval appears under the population graph. What does the red half circle at the bottom of the page represent? The sample mean, which changes each time we take a sample. The true population mean, which changes each time we take a sample. The sample mean, which does not change each time we take a sample. The true population mean, which does not change each time we take a sample