chapter 3

Question 1

what is the mode?

Answer 1

the value that occurs most often

Question 2

what is the median?

Answer 2

the middle value in a list after they have been put in order

Question 3

how to figure out the median from a group of data values with an odd amount?

Answer 3

1/2(n+1)

Question 4

how to figure out the median from a group of data values with an even amount?

Answer 4

n/2

Question 5

what is the mode of data in a frequency table?

Answer 5

the category or class with the highest frequency

Question 6

what is the median of data from a frequency data?

Answer 6

1/2(n+1)th value

Question 7

how to figure out the mean from a frequency data for discrete data?

Answer 7

total fx/ x

Question 8

what is the median for grouped continuous data?

Answer 8

1/2nth

Question 8

how to figure out the upper quartile from discrete data?

Answer 8

3/4 (n+1)

Question 8

what are percentiles?

Answer 8

when a set of data is divided into 100 equal parts

Question 8

how to figure out the median from discrete data?

Answer 8

1/2 (n+1)

Question 8

how to figure out the lower quartile from discrete data?

Answer 8

1/4 (n+1)

Question 9

what are deciles?

Answer 9

when data is divided into 10 equal parts

Question 10

what is standard deviation a measure of?

Answer 10

a measure of how much the values deviate from the mean value/ how spread out they are

Question 11

what does a box plot represent?

Answer 11

• maximum & minimum values
• median & upper and lower quartiles

Question 12

what is an outlier?

Answer 12

• any value that is more than 1.5 times the IQR below the LQ
• any value that is more than 1.5 times the IQR above the UQ

Question 13

what is an outlier (in terms of standard deviation and mean)?

Answer 13

a value more than 3 standard deviations from the mean

Question 14

positive skew in box plots?

Answer 14

median close to the LQ

Question 15

negative skew in box plots?

Answer 15

median close to the UQ

Question 16

positive skew- mean, modian and mode?

Answer 16

mean > median > mode

Question 17

negative skew- mean, median and mode?

Answer 17

mode > median > mean

Question 18

a positive value means what for the skew?

Answer 18

positive skew

Question 19

a negative value means what for the skew?

Answer 19

negative skew

Question 20

advantages of the mode?

Answer 20

• easy to find
• can be used with any type of data
• unaffected by open- ended or extreme values

Question 21

disadvantages of the mode?

Answer 21

• there may be no mode/ there may be more than one
• cant be used to calculate a measure of spread

Question 22

advantages of the median?

Answer 22

• easy to calculate
• unaffected by extreme values
• best to use when data is skewed
• can be used to calculate quartiles, IQR and skew

Question 23

disadvantages of the median?

Answer 23

• may not be a data value

Question 24

advantages of the mean?

Answer 24

• uses all the data
• can be used to calculate standard deviation & skew

Question 25

disadvantages of the mean?

Answer 25

• always affected by extreme values
• can be distorted by open-ended classes

Question 26

what do you need to compare 2 or more data sets?

Answer 26

• need to compare at least an average and a measure of spread
• or you can compare the skew of the distribution