Biostats Chapter Two

Front 1

frequency distribution

Back 1

lists data calues (either individually or by groups of intervals), along with their corresponding frequencies (or counts)

Front 2

lower class limits

Back 2

smallest numbers that can belong to the different classes

Front 3

upper class limits

Back 3

largest numbers that belong to the different classes

Front 4

class boundaries

Back 4

numbers used to seperate classes, but without the gaps created by class limits. they are obtained as follows: find the size of the gap between the upper class limit of one class and the lower classe limit of the next class, add half of that amount to each upper class limit to find the upper class boundaries and subtract half that amount from each lower class limit to find the lower class boundaries

Front 5

class midpoints

Back 5

midpoints of the classes, each class midpoint can be found by adding the lower class limit to the upper class limit and dividing the sum by two

Front 6

class width

Back 6

difference between two consecutive lower class limits or two consecutive lower class boundaries

Front 7

histogram

Back 7

bar graph in which horizontal scale represents calsses of data values and the vertical scale represents frequencies, the heights of the bars are drawn adjacent to each other (without gaps)

Front 8

measure of center

Back 8

a value at the center of middle of a data set

Front 9

arithmetic mean

Back 9

measure of the center found by adding the values and dividing the total by the number of values

Front 10

median

Back 10

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

Front 11

mode

Back 11

value that occurs most frequently

Front 12

bimodal

Back 12

two values occur iwth the same greatest frequency

Front 13

multimodal

Back 13

more than two values occur with the same greatest frequency, each is a mode

Front 14

midrange

Back 14

measure of the center that is the value midway between the highest and lowest values inthe original data set, found by adding the highest data value to the lowerst data value and then dividing the sum by two

Front 15

skewed

Back 15

distribution of data is skewed if it is not symmetric and extends more to one side than the other

Front 16

range

Back 16

the difference in a set of data between the maximum and minimum value

Front 17

standard of deviation

Back 17

measure of the variation of values about the mean, it is a type of average deviation of values from the mean that is calculated

Front 18

variance

Back 18

measure of variation equal to the square of the standard deviation

Front 19

sample variance

Back 19

square of the standard deviation s

Front 20

population variance

Back 20

square of the popluation standard deviation sigma

Front 21

standardized score

Back 21

z score-numer of standard deviations that a given value x is above or below the mean

Front 22

5-number summary

Back 22

consists of the minimum value, the first quartile (Q1), the median (or second quartile Q2), the third quartile (Q3), and the maximum value

Front 23

boxplot

Back 23

box and whisker digram-graph of a data set that consists of a line extending from the minimum value to the maximum value, and a box with lines drawn at the first quartile, median and third quartile