Lecture 5

Question 1

an element, feature, or factor that is liable to vary or change

Answer 1

factor

Question 2

a quantity that during a calculation is assumed to vary or be capable of varying in value

Answer 2

mathematics variable

Question 3

a data item that may take on more than one value during the runtime of a program

Answer 3

computing variable

Question 4

4 scale of measurement data types

Answer 4

nominal, ordinal, continuous(interval and ratio)

Question 5

a measurement scale based on the classification of an observation according to the group to which it belongs – a process of categorization

Answer 5

nominal

Question 6

examples of nominal classification

Answer 6

gender, political party, martial status

Question 7

a measurement scale based on the classification of an observation according to its relationship to other observations

Answer 7

ordinal

Question 8

examples of ordinal classification

Answer 8

poor, fair, good rating scale

Question 9

numbers can represent __ and __ scale values but just because numbers are used doesn’t mean that they represent “true numbers” that can be added and subtracted

Answer 9

nominal and ordinal

Question 10

a measurement scale characterized by equal units of measurement, zero point is arbitrary, the distance between any two numbers is of known size

Answer 10

interval

Question 11

examples of interval classification

Answer 11

fahrenheit and centigrade temp scales

Question 12

a measurement scale characterized by equal units of measurement and a true zero point at its origin

Answer 12

ratio

Question 13

examples of ratio classification

Answer 13

mass, time

Question 14

populations use __ for constants, not variables

Answer 14

greek symbols

Question 15

samples use __ for variables

Answer 15

roman characters

Question 16

measures of location or central tendency

Answer 16

mode, median, mean

Question 17

the value of the most frequent measurement, most useful with the nominal scale, but may be used with any scale, there could be more than one

Answer 17

mode

Question 18

the value of the measurement that falls in the middle when the measurements are arranged in order of magnitude

Answer 18

median

Question 19

the point at which or below which 50% of the measurements fall

Answer 19

median

Question 20

probably most useful with the ordinal scale, but may be used with higher order scales

Answer 20

median

Question 21

the arithmetical average, the sum of the measurements divided by the total number of measurements

Answer 21

mean

Question 22

most useful with interval or ratio measurements scales

Answer 22

mean

Question 23

range, interquartile range, variance, standard deviation, coefficient of variation, standard error of the mean

Answer 23

measures of variability or dispersion

Question 24

the difference between the largest and smallest measurements

Answer 24

range

Question 25

Xmax - Xmin

Answer 25

range

Question 26

X25th percentile - X75th percentile

Answer 26

interquartile range

Question 27

s^2, MS, mean square

Answer 27

variance

Question 28

the average of the square of the deviations of the measurements about their mean

Answer 28

variance

Question 29

__ is considered in terms of the distance of each measurement from the mean, generally associated with the term “degrees of freedom, df)

Answer 29

variance

Question 30

variance is determined by

Answer 30

find mean, subtract this mean from each measurement and square the result to eliminate negative numbers

Question 31

the sum of squared in the first two steps on determining the variance is called ___

Answer 31

sum of squares

Question 32

dividing the sum of squares in variance by the number in the smaple inus one gives us the __, gives us an unbiased estimate of the population variance

Answer 32

sample variance

Question 33

the positive square root of the variance

Answer 33

standard deviation

Question 34

the standard deviation is calculated by taking the square root of the

Answer 34

square root of the variance

Question 35

measures the percentage of spread, unitless, allows for caparisons

Answer 35

coefficient of variation

Question 36

states that the sampling distribution of the mean of any independent, random variable will be normal or nearly normal, if the sample size is large enough

Answer 36

central limit theorem

Question 37

if we took several samples from a population, calculated the mean of each sample, and then calculated the SD of these sample means, we would have

Answer 37

the standard error of the mean

Question 38

can be calculated from a single sample by dividing the SD by the square root of N

Answer 38

standard error of the mean

Question 39

an estimate of the variability of individual measurements within a sample, also is used to measure variability of individual subjects around a sample mean

Answer 39

standard deviation

Question 40

an estimate of the variability of sample means about the population mean, also is used to assess how accurately a sample mean reflects a population mean

Answer 40

standard error of the mean