ch 2. presenting data

Question 1

frequency distribution defn

Answer 1

• Frequency distribution shows the freq of each meas of a variable (in a table)

Question 2

relative frequency defn

Answer 2

• Relative frequency- the number of times a partic observation occurs divided by the total number of observations

Question 3

what would present a bigger picture the relative freq or the freq distibution

Answer 3

freq distribution

Question 4

cumulative freq defn

Answer 4

• Cumulative frequency lists the number of observations with a value less than the max value of the variable interval see page 15 eg if you have 9 pts discharged on day 3 or earlier the total includes all pts that stayed 0,1,2,3 days added up.

Question 5

cumulative relative freq

Answer 5

calculated by adding together all the relative freq less than or equal to the selected upper limit point

can make it into % to understand better

Question 6

grouped freq

Answer 6

• Grouped frequencies are freq distributions with distinct intervals or groups to simplify info.

Question 7

what is the drawback of using grouped frequencies

Answer 7

Some info is lost this way esp if you use large intervals

Question 8

cumulative percentage defn

Answer 8

• Cumulative percentage-the % of obs with a value less than the max value of the variable interval (same idea as cumulative freq but in %)

Question 9

what is a quantile

Answer 9

• Quantiles—two kinds-percentiles and quartiles

Question 10

quartile

how is a percentile different

Answer 10

(divide a data set into four equal parts with first uartile being the 25th percentile, second quartile is 50th percentile etc)

percentile divides a data set into 100 equal portions

Question 11

percentile rank

Answer 11

the % of observations lower than that score in a freq distribution

Question 12

what kind of data does a bar chart show

is it often used when each answer is distinct and in no particular order

Answer 12

• Bar chart-show nominal categorical data. Often used when there are spaces between bars and each answer is distinct and in no partic order

Question 13

histogram defn

what kind of data are they gen used for

Answer 13

• Histograms are a type of bar chart often w no spaces bet bars as theyre often for continuous or ordinal data

Question 14

what kind of data are line graphs best for showing

Answer 14

• Line graphs are best for showing continuous variables that change over time

Question 15

outlier defn

Answer 15

• Outliers are data that are outside the expected relationship

Question 16

scatterplot

Answer 16

• Scatterplots . each point shows how one subject relates to two variables

Question 17

what does it mean when points are close together or seem to follow a line closely

Answer 17

the relationship bet variables on horizontal and vertical axes are relatively strong

Question 18

if scatterplot indicates positive relationship what would this look like

and negative

Answer 18

o When the dots go from bottom left and go up this indicates a positive relationship (as one inc the other inc as well eg ht and wt)
o If they start in upper left and go down towards right then its neg relationship

Question 19

if charting nominal data what might you use

Answer 19

bar chart

Question 20

if wanting to graph ordinal or continuous data might use

Answer 20

histogram

Question 21

to graph continuous variables that change over time might use

Answer 21

scatterplot