Intro to Stats

Question 1

population

Answer 1

complete collection of all indivs to be studied

Question 1

sample

Answer 1

subcollection of members selected from a population

Question 2

variables

Answer 2

characteristics about the population you want to learn about or measure

i.e height, weight, BP

Question 3

parameter

Answer 3

mathematical description of some characteristic/variable for a population

i.e population mean

Question 4

statistic

Answer 4

mathematical description of some characteristic/variable for a sample

same as parameter just with a sample instead

Question 5

descriptive stats

Answer 5

used to summarize and describe characteristics of data numerically and graphically

i.e sample mean AND standard deviation for age of ER pts

Question 6

inferential stats

Answer 6

used to make conclusions/inferences about populations

Question 7

types of data

Answer 7

1. categorical- aka qualitative, consists of names or labels
2. quantitative- aka numerical, numbers representing counts or measurements

Question 8

subtypes of quantitative

Answer 8

1. discrete- number of possible values is finite/countable
2. continuous- numerical, infinitely many possible values w/ some continuous scale

Question 9

measurement

Answer 9

another way to classify data to use scales of measurement

aka assignment of values to outcomes

Question 10

scales of measurement

Answer 10

nominal
ordinal
interval
ratio

Question 11

nominal level

Answer 11

names/labels/categories that CANNOT be ordered

least precise level of measurement

i.e f/m gender, y/n responses, survey, vitamins

categories only

Question 12

ordinal level

Answer 12

can be ordered
gaps b/t data cannot be determined/are meaningless

i.e pain scale

categories with some order

Question 13

interval level

Answer 13

ordered
gaps b/t data ARE meaningful
NO natural zero

i.e temperature scale, pH values

ordinal + meaning aka differences but no natural starting pt

Question 14

ratio level

Answer 14

interval + natural zero aka 0= none

most precise scale of measurement

i.e. heart beat, blood pressure

difference and natural starting pt

Question 15

experiment

Answer 15

apply some treatment then observe its effects on subjects

subjects called experimental units

gold standard
random assignment of subjects

Question 16

observational study

Answer 16

observing and measuring specific characteristics w/o modifying subjects

aka no manipulation

Question 17

probability sampling

Answer 17

selecting members from a pop so that each has a known chance of being selected

Question 18

simple random sample

Answer 18

indiv chosen randomly and entirely by chance aka** same probability** of being chosen at any stage during sampling process

via random generator on computer

Question 19

systematic sampling

Answer 19

select some starting point and then select every kth element in pop

Question 20

stratified sampling

Answer 20

subdivide pop into at least two different subgroups that share same characteristics

then draw sample/stratum from each subgroup

Question 21

cluster sampling

Answer 21

divide pop area into sections/clusters

randomly select some of clusters

choose all members from selected clusters

Question 22

multistage sampling

Answer 22

collect data by using combo of basic sampling methods

pollsters select a sample in diff stages- each stage might use diff methods of sampling

Question 23

non-probability sampling

Answer 23

often biased so results not necessarily valid

voluntary response sample or self selected

write in or call ins

Question 24

convenience sampling

Answer 24

results that are easy to get

Question 25

key concepts of data presentation

Answer 25

organize and summarize with frequency distribution to understand nature of data

Question 26

frequency distribution/table

Answer 26

shows how data is partitioned among several categories/classes

list categories w/ number of data values in each

can be relative (%) or cumulative

Question 27

histogram

Answer 27

graph w/ bars of equal width drawn adj to each other/without gaps

x axis = classes of quantitative data values
y axis= frequencies w/ heights of bars corresponding to frequency value

can be relative (%) too

Question 28

frequency polygon

Answer 28

line segments connected to points directly above class midpoint values

can be relative too (proportions of %)

Question 29

ogive

Answer 29

line graph w/ cumulative freq