stats other stuff

Question 1

how do you calculate a marginal distribution

Answer 1

take every value in a column or row of a table and add them together, then divide by the table’s total

Question 2

how do you calculate a conditional distribution

Answer 2

take one specific variable and divide it by its category (ex: girls with blue eyes divided by girls, when men with different colored eyes are also included in the table)

Question 3

what is a confounding variable

Answer 3

an outside variable that can cause disruption in a distribution’s results

Question 4

what type of graph is good for categorical data

Answer 4

bar graphs and pie charts

Question 5

what type of graph is good for quantitative data

Answer 5

dot plots

Question 6

why is it important to start the y axis of a graph on 0

Answer 6

starting the y axis on a higher number may cause exaggerated results

Question 7

what acronym should you use to describe a distribution’s properties

Answer 7

SOCS (shape, outliers, center, and spread)

Question 8

how do you interpret a stem and leaf plot

Answer 8

Digits in the stem represent the numbers first digit(s) and leafs represent the numbers second digit

Question 9

what type of data uses histograms

Answer 9

quantitative

Question 10

what is the difference in bar graphs and histograms

Answer 10

histograms are for quantitative data and their bars represent a range of data, but bar graphs are for categorical data and their bars represent specific values

Question 11

what is the difference in X bar and Mu (mean variables)

Answer 11

X bar represents the sample mean, while Mu represents the population mean

Question 12

which type of distribution is described using mean and standard deviation

Answer 12

Normal distribution (symmetric)

Question 13

what type of distribution is described using median and IQR

Answer 13

A skewed distribution

Question 14

what percentile is Q1

Answer 14

25th

Question 15

what percentile is Q2

Answer 15

50th

Question 16

what percentile is Q3

Answer 16

75th (meaning 75% of the data values fall below the value of Q3)

Question 17

how do you calculate the high outliers in a data set

Answer 17

low outliers occur if points are higher than what you get when you calculate Q3 + (IQR x 1.5)

Question 18

how do you calculate the low outliers in a data set

Answer 18

low outliers occur if they are less than what you get when you calculate Q1- (IQR x 1.5)

Question 19

what elements does adding and subtracting affect in a distribution

Answer 19

mean and median but not spread (IQR or standard deviation)

Question 20

what acronym should you use to describe correlation and scatterplots

Answer 20

DUFS (direction, unusual points, form: whether its linear or not, and strength)

Question 21

what is the meaning of r2

Answer 21

how much of the data can be accounted for or explained by the independent variable in a distruibution

Question 22

what does correlation require

Answer 22

that both variables are quantitative

Question 23

how do you calculate residuals

Answer 23

Actual value - predicted value

Question 24

a census…

Answer 24

collects data from every individual in a population

Question 25

what is a simple random sample

Answer 25

a sample taken from a population where every individual has equal chance of being chosen

Question 26

blocking helps to

Answer 26

take away confounding variables by separating individuals in a data set into groups of shared characteristics

Question 27

undercoverage bias

Answer 27

some members can’t be chosen

Question 28

nonresponse bias

Answer 28

individual can’t be contacted or refuses to participate

Question 29

response bias

Answer 29

instances include when individuals lie

Question 30

wording of a question bias

Answer 30

when the question urges certain answers out

Question 31

what is a control in statistics

Answer 31

when other variables that may affect the response are kept the same for all groups

Question 32

replication

Answer 32

use enough groups to see more accuracy in affects

Question 33

statistically significant

Answer 33

when an observation has an affect so large it could not have happened by chance DOES IMPLY CAUSATION