week 7

Question 1

count data categories must be

Answer 1

mutually exclusive and exhaustive
mutually exclusive = can not be in more than one category
exhuastive = categories represent all options seen within data

Question 2

four requirements of binomial experiments

Answer 2

1. have a set number of identical trials
2. have only two possible outcomes for each trial (eg yes/no)
3. have mutually exclusive and exhaustive outcomes for each trial
4. the probabilities of occurrence for the two categories must be constant across all the trials (expected values)

Question 3

the centre of the distribution of sample proportion is

Answer 3

p-hat

Question 4

the SD of the distribution of sample proportion is

Answer 4

square root of (p-hat)(q-hat)

Question 5

variability is maximized when p-hat is

Answer 5

0.5

Question 6

the further from 0.5 the smaller the

Answer 6

standard deviation

Question 7

cohens D

Answer 7

difference between the sample proportion and the population proportion, all divided by the standard deviation of the population

Question 8

the width of CI is

Answer 8

twice the bound of CI

Question 9

the largest variance of a binomial variable is

Answer 9

0.25

Question 10

variability is maximized when p hat =

Answer 10

0.5

Question 11

what is often a better choice for the presentation of proportional data

Answer 11

count data

Question 12

chi square is a test of

Answer 12

model fit

Question 13

what is the z distribution

Answer 13

the standard normal distribution

Question 14

how can a test of two independent proportions be conducted

Answer 14

z-test

2x2chi square test of independence

Question 15

what does count data refer to

Answer 15

categorical random variables

Question 16

what is the simplist form of categorical data

Answer 16

dichotomous variable

Question 17

how many trials is a bernoulli trial

Answer 17

a single trial

Question 18

what is the mean and SD for bernoulli distributions

Answer 18

SD = square root of pq
mean= p

Question 19

what happens to SD as p-hat moves further away from 0.5

Answer 19

gets smaller

Question 20

the width is twice the

Answer 20

bound

Question 21

as variance increases the width

Answer 21

increases

Question 22

two advantages of presenting proportional data as frequencies

Answer 22

1. reminds the researcher to present total n size
2. allows comparison of more than two proportions

Question 23

what statistic will we use for count data analysis

Answer 23

chi-square calculations