Chapter 3

Question 1

descriptive statistics

Answer 1

quantities that capture important features of frequency distributions

Question 2

What are the most important descriptive stats for numerical data?

Answer 2

those measuring LOCATION of a frequency distribution (tells us avg) and its SPREAD (tells how variable the measurements are around the center)

Question 3

What are the most important descriptive stats for categorical data?

Answer 3

proportion (measures fraction of observations in a given category)

Question 4

Coefficient of variation

Answer 4

the st.dev expressed as a % of the mean

high CV, more variability

Question 5

Interquartile Range

Answer 5

the span of the middle half of the data, from the 1st quartile to the 3rd

Question 6

Boxplot

Answer 6

displays median and IQR along with other quantities of the frequency distribution

Question 7

When data is skewed/has extremities, is IQR or st.dev better as an indicator of the spread?

Answer 7

IQR

Question 8

Quantile

Answer 8

(of a measurement) specifies the fraction of observations less than or equal to it

Question 9

Identify 3 measures of location

Answer 9

mean, median, mode

Question 10

Identify 3 measures of variability

Answer 10

SD, variance, range

Question 11

Standard deviation

Answer 11

measure of the spread that indicates how different measurements are from the mean