Chapter 6: comparing two means (independent samples)

Question 1

What is a percentile?

Answer 1

For any set of n measurements, the pth percentile is a number such that p% of the measurements fall below the pth percentile and (100-p)% of the measurements fall above it

Question 2

What is the 1st lower quartile?

Answer 2

the 25th percentile, denoted as Q1 or QL.
This is the median of the lower half of the data set.

Question 3

What is the 50th percentile?

Answer 3

also known as the second quartile or Q2, it is the median

Question 4

What is the third quartile?

Answer 4

this is the 75th percentile, and denoted as Q3 or QU
- this is the median of the upper half of the data set

Question 5

How do you find quartiles when there are odd vs even numbers of observations in a dataset?

Answer 5

odd: omit the middle observation
even: include all observations

Question 6

What is the interquartile range?

Answer 6

IQR is the difference between the first and third quartiles

Question 7

Is the IQR a resistant measure of variation?

Answer 7

YES

Question 8

What is included in the 5 number summary?

Answer 8

minimum, QL, M, QU, Maximum

Question 9

How are the lower inner, and upper inner fences calculated?

Answer 9

Lower inner fence: Ql-1.5(IQR)
Upper inner fence: Qu-1.5(IQR)

Question 10

When is a value considered a suspected outlier?

Answer 10

when observations are outside of the upper inner and lower inner fences

Question 11

What is an adjacent value?

Answer 11

the most extreme observations that still lie within the lower and upper inner fences