Question

Why are population mean and population proportions reported as estimates in studies?
How does a histogram indicate a normal distribution?
How could you use a dot plot or stem-and-leaf plot to indicate a normal distribution?

Answer 1

1. We don't know the proportion of the population so you use point estimates to find the appropriate standard deviation.
2. The shape is normal if the graph is bell-shaped and symmetric about the mean.
3. A frequency distribution table or a histogram for the values or you can use a dot plot or stem and leaf plot and let the numbers themselves show the same information. Otherwise, they show the same frequency
Hope this helps :)