If you had to pick one statistical concept as the most important and valuable concept which would you pick and explain in detail why?

(please select from below)

Variables and measures of data

sampling methods

comparing sampling methods

sampling error, bias, and misleading statistics *

frequency tables and histograms

dot plots and stem and leaf plots

line and bar graphs

interpreting graphs

impact of outliers on measures of central tendency

distribution shape

standard deviation

quartiles and box plots introduction to Empirical Rule and Chebyshev's Theorem

parameters of the normal distribution

linear regression equations

predictions using linear regression

least-squares and outliners

correlation and causation

parameters of binomial distribution

probability using the normal distribution

standard error

confidence interval for mean - population standard deviation known

confidence interval for mean - population standard deviation unknown

confidence intervals for population proportion

hypothesis testing

hypothesis test of mean - population standard deviation known

hypothesis test of mean - population standard deviation unknown

conduct a hypothesis test for mean - population standard deviation unknown - critical value/rejection region approach

hypothesis test for proportion