Chapter 2 Describing distributions with Numbers

Question 1

What is the mean?

Answer 1

The average which is calculated adding all of the numbers up and dividing by the amount of numbers there are

Question 2

The mean is considered the ____ _____ of the distribution

Answer 2

Balance point

Question 3

What is the median (M) ?

Answer 3

The midpoint of a distribution
If even: the average of the two middle numbers
if odd: the middle number

Question 4

When getting the median do you need to rearrange the numbers in numerical order?

Answer 4

Yes

Question 5

Can outliers influence the mean?

Answer 5

Yes the mean is not a resistant measure of center

Question 6

Is the median (M) a resistant measure of center?

Answer 6

Yes, it will change but less than the mean

Question 7

which one would be more affected by an outlier?
a: mean
b: median

Answer 7

a: mean

Question 8

If a distribution is roughly symmetric that means the mean and median (M) are _____

Answer 8

close together

Question 9

If a distribution is completely symmetric that means the mean and median (M) are _____

Answer 9

exactly the same

Question 10

If something is right skewed that means the mean is _____ than the median (M)

Answer 10

higher

Question 11

If something is left skewed that means the mean is ____ than the median (M)

Answer 11

lower

Question 12

Which measure of center is most appropriate for heavily skewed data sets?

Answer 12

The median (M) since it is not affected by outliers as much as the mean

Question 13

What is the first quartile (Q1) in a sample?

Answer 13

The quartile that has 25% of the data at or below it (to the left of the median (M))

Question 14

What is the second quartile (Q2) in a sample?

Answer 14

the median (M)

Question 15

What is the third quartile (Q3) in a sample?

Answer 15

The quartile that has 75% of the data at or below it (to the right of median (M))

Question 16

What is the interquartile range (IQR)?

Answer 16

The amount of spread in the middle of a data set

Question 17

How do you find the interquartile range (IQR)?

Answer 17

Q3-Q1=IQR

Question 18

What is the Q1 in Q1 of a data set?

Answer 18

The median (M) of that set

Question 19

What is Q3 in Q3 of a data set?

Answer 19

the median (M) of that set

Question 20

What is the 5 number summary

Answer 20

Smallest observation (Minimum), Q1, the median (M), Q3, the largest observation (Maximum)

Question 21

What does M mean?

Answer 21

Median

Question 22

What is a box plot?

Answer 22

A graphical display that shows the 5 number summary

Question 23

How do you know a box plot is skewed right?

Answer 23

If the tail is longer on the right

Question 24

How do you know a box plot is skewed left?

Answer 24

If the tail is longer on the left

Question 25

What is a modified box plot?

Answer 25

A box plot that shows suspected outliers as circles, dots, or another symbol

Question 26

What is the standard deviation?

Answer 26

it describes the spread of the data in relation to the mean

Question 27

which of these is not resistant to an outlier? a: mean b: median (M) c: standard deviation (σ/s)

Answer 27

a: mean c: standard deviation (σ/s)

Question 28

What is Xbar?

Answer 28

The symbol for sample mean

Question 29

What is n?

Answer 29

number of data points in a sample

Question 30

what is ΣXi?

Answer 30

the sum of all the data points

Question 31

what is S?

Answer 31

standard deviation

Question 32

what is s2?

Answer 32

the variance

Question 33

what is the formula for variance (S2) in a sample?

Answer 33

s2=Σ(Xi-X̅)2 -------------- n-1

Question 34

how do you find the standard deviation (σ/s) in a sample?

Answer 34

square root of variance

Question 35

what is σ/s?

Answer 35

standard deviation

Question 36

what does standard deviation (σ/s) measure?

Answer 36

the spread about the mean and is used when the mean is the most appropriate measure of center.