descriptive statistics

Question 1

observation on one variable may be shown visually by putting variables on one axis and putting the frequency on the other

Answer 1

visual presentation of data

Question 2

they are best used to interpret the frequency distribution visually

Answer 2

histogram:
y axis - no. of units
x axis - measurement lvl
bars are visually proportional to e/o

frequency polygon:
shorthanded presents a histogram
dot is placed at top of bars then connected = polygon (must be shaded)
better enunciates the data shape
the graph starts and ends at zero to “close” the shape

line graph:
can illustrate more than one data sets in one graph
- arithmetic line graph
- semilogarithmic line graph

Question 3

differences between histogram, frequency polygon and line graph

Answer 3

histogram - data distribution
frequency polygon - connects those bar’s midpoints with lines
line graph - trends/ changes over time

Question 3

briefly explain
arithmetic line graph:
semilogarithmic line graph:

Answer 3

arithmetic line graph:
both x and y axis has arithmetic scale (numerical)

semilogarithmic line graph: y axis has logarithmic axes

arithmetic - evenly spaced interval semilogarithmic -scale increase by multiples bcs of the exponential changes (bacteria)

Question 4

it is how well distributed are the instances of a data

Answer 4

frequency distribution

Question 4

frequency distribution from ____ data is defined by …

Answer 4

continuous data
types of descriptors aka parameters

Question 5

what are the types of parameters of a frequency distribution

Answer 5

central tendency
dispersion

Question 6

it is defined as the value used to represent the center or the middle of a set of data values

Answer 6

central tendency

Question 7

it locates observations on a measurement scale

Answer 7

central tendency

Question 8

it describes the spread of values in a given data set

Answer 8

dispersion

Question 9

it suggest how widely spread out the observations are

Answer 9

dispersion

Question 10

high SD =
low SD =

Answer 10

high SD = scattered data or spread out far from the mean
low SD =clumped data around the mean

Question 11

it is the average or the sum (∑) of all observer values (xi) divided by the total no. of observation (N)

Answer 11

mean, x̄

Question 12

it has the most mathematical properties and is most representative of the dataset if not for outliers.

Answer 12

mean, x̄

Question 13

in median, the middle has been arranged from ____ to ____

Answer 13

highest to lowest

Question 14

median is
frequently used in -
rarely -

Answer 14

• healthcare and economics
• used to make inferential conclusion from

Question 15

it is the most commonly observed value

Answer 15

mode

Question 16

true or false:
mode is frequently used in statistics

Answer 16

false - seldomly

Question 17

arithmetic mean:
weighted mean:

Answer 17

arithmetic mean: for each indiv observation
weighted mean calculated by multiplying the weight associated with a particular outcome (grading system)

Question 18

what are the downside of using mode as a measure of central tendency

Answer 18

may have no mode
have more than one mode

Question 19

it is a statical measurement of the spread between numbers in a data set

Answer 19

variance

Question 20

The differenced between the observed value of a data point and the Expected value is known as deviation in statistics.

Answer 20

mean deviation

it is the average deviation of a data point from the mean, median or mode of the data set.

Question 20

It measures how far each number in the set is from the mean and thus from every other in the set

Answer 20

variance

Question 21

it is the average amount of variability in your dataset.

Answer 21

SD

Question 22

mean deviation is aka

Answer 22

mean absolute deviation

Question 23

values that split sorted data or a probability distribution into equal parts

Answer 23

quantiles

Question 24

a statistical term that describes a division of observation into four defined intervals based on the values of the data and how they compare to the entire set of observations.

Answer 24

quartiles

lower Q
median Q
upper Q

Question 25

how to calculate percentiles

Answer 25

data ordered from lowest to highest
divided into 100 equal parts

Question 26

how to find range

Answer 26

highest value minus lowest value

Question 27

In descriptive statistics, the range of a set of data is the size of the narrowest interval which contains all the data.

Answer 27

range
IQR

Question 28

it is defined as as the difference between third and the first quartile.

Answer 28

IQR

Question 29

a measure of asymmetry of a distribution
explain why it is asymmetry

Answer 29

skewness (horizontal imbalance)
because left and right images are not mirror images

Question 30

it is used to help measure how data disperse between a distribution’s center and tails, with larger values indicating a data distribution may have “heavy” tails that are thickly concentrated with observations or that are long with extreme observations

Answer 30

kurtosis (vertical imbalance)