CH 3 Describing, Exploring and Comparing Data

Question 1

What term is a value at the center or middle of a data set?

Answer 1

Measure of center

Question 2

What set of data is the measure of center found by adding all the data values and dividing the total by the number of data values?

Answer 2

Mean or arithmetic mean

Question 3

What term describes a statistic that, in the presence of extreme values, it does not change very much?

Answer 3

resistant

Question 4

What are some disadvantages of mean?

Answer 4

is is not resistant an extreme value can change the value substantially

Question 5

What is the formula for mean?

Answer 5

Question 6

What is the formula for the mean of a set of sample values?

Answer 6

Question 7

What is the fromula for the mean of all values in a population?

Answer 7

Question 8

What data set is the measure of center that is the middle value when the original data values are arranged in order of increasing (or decreasing) magnitude?

Answer 8

median

Question 9

How do you find the median?

Answer 9

sort values in order

if the number of data values is odd, the median is the number located in the center

if the number of data values is even, the median found by computing the mean of the two middle numbers

Question 10

What data set is the value(s) that occur with the greatest frequency?

Answer 10

mode

Question 11

What type of data is mode used with?

Answer 11

qualitative data (names, labels, categories)

Question 12

When calculating the mode, how would you describe the data if two values occured with the same greatest frequency?

Answer 12

bimodal

mulitmodal - more than two

Question 13

What is the measure of center that is the value midway between the maximum and minimum values in the original data set?

Answer 13

midrange

Question 14

How do you calculate the midrange of a data set?

Answer 14

Midrange = (max data value + min data value) / 2

Question 15

What are the round-off rules for measures of center?

Answer 15

for the mean, median and midrange, carry one more decimal place than is present in the original set of values

for the mode, leave the value as is without rounding

Question 16

What is the formula used to caluculate mean from a frequency distribution?

Answer 16

Question 17

What is the formula for calculating weighted mean?

Answer 17

Question 18

What set of data values is the differnece between the maximum data value and the minimum data value?

Answer 18

range

Question 19

What is a measure of how much data values deviate away from the mean?

Answer 19

standard deviation

Question 20

What is the formula for sample standard deviation?

Answer 20

Question 21

List the steps for for finding the standard deviation of the following:

84 74 50 60 52

Answer 21

1. Compute the mean (64)
2. Subtract the mean from each (20 10 -14 -4 -12)
3. Square each dviation obtained from the previous step
4. Add all the squars obtained
5. Divide total by n-1
6. Find the square root of the results

Question 22

What is the Range Rule of Thumb for Estimating a Value of the Standard Deviation?

Answer 22

Question 23

What is the symbol for the mean of a sample and a population?

Answer 23

Question 24

What is the formula for finding the standard deviation of a population?

Answer 24

Question 25

What term is defined as a measure of vatiation equal to the square of the standard deviation?

Answer 25

variance

Question 26

How do articles in professional journals often abbreviate standard deviation and varieance?

Answer 26

SD

VAR

Question 27

List the symbols for :

Sample standard deviation

Sample variance

Population standard deviation

Population variance

Answer 27

Question 28

What should you use when comparing variation in samples or populations with very differernt means?

Answer 28

coefficient variation

Question 29

What is the formula for calculating coefficient of variation?

Answer 29