2.4 Variance and standard deviation

Question 1

What is Sxx?

Answer 1

» Summary statistic is variance

Question 2

What is the formula for variance?

Answer 2

» The sum of x^2 over n minus the (mean of x)^2

Question 3

What is Sxx equal to in a formula?

Answer 3

» Sum of x^2 - (mean)^2

Question 4

What is standard deviation?

Answer 4

» Square root of the variance

Question 5

What is the symbol to denote standard deviation?

Answer 5

» small sigma

Question 6

How can you find the data in a grouped frequency table?

Answer 6

» You can estimate the variance and standard deviation using the midpoint of each class interval