intro to stats exam 1

nominal level

data that is classified into categories. (ex: types of cars)

ordinal level

data arranged in some order

interval level

has oridnal, has measurable spaces between values

ratio level

has true zero

categorical (qualitative) variables

type of data that is categorized (NOT a measurement of level)

quantitative variables

data that is separated by counts or measures (discrete or continuous variables)

discrete variables

quantitative variables that are counted

continous variables

quantitative variables that are measured

nominal

What level of measurement? car

ordinal

What level of measurement? 0 to 10 numerical pain scale where 0=no pain and 10 = worst pain imaginable

interval

What level of measurement? CALANDER YEARS like 44 BCE

ratio

what level of measurement? 0km/50km

random sample

population is chosen randomly for sample

systematic sample

population has starting point, then selected at every n value

stratified sample

population divided into groups, then sample drawn from each group

cluster sample

population divided into groups

convenience sample

results that are easy to get

volutneer sampling

self selected replies

population

all subjects studying

parameter

A numerical value describing a characteristic of the entire population.

sample

group of subjects selected from population

statistic

the smaller subset of the population actually examined.

descriptive statistics

collecting, organizing, presenting, and summarizing known data. uses entire data set: mean, median, mode, charts, graph.

inferential statistics

about the whole population - what the sample tells us about the bigger group we couldnt measure. hypothesis and drawing conclusions

variable

The specific characteristic being measured or observed for each individual.

grouped frequency distribution

used for a large set of quantiative data with many different values and data is grouped. How much data in this group

cumulative frequency

how many data points fall at our below upper bound

relative frequency

what fraction or percent the entire data set in that group represents

cumulative relative frequency

what percentage of the entire data set is packed underneath a given “cut off” of the class

80% above, 20% below.

If I am in the 20th percentile of all test scores, and I got a 62, How many people scored above me? How many people scored equal than me or BELOW me?

one more

You round the mean _____ than the data set

one more

You round the standard deviation ____ than the data set.

one more

You round the median ____ than the data set.

3, 1, cumulative relative

You round the relative frequency to _____ decimal places or ___ decimal place when converted to percentage. It is the same for ________ frequency.

observational study

records data on subjects. does not change anything. proves association.

experimental study

direct manipulation. researchers assign treatments to groups. proving causation.

[Minus 1 from the last number and add .5, add 0.5)

How to calculate lower boundary? Upper boundary? Include proper notation

[1.335, 1.345)

what is the boundary for 1.34?

suspicious samples

The sample is not large enough which generates many kinds of results. The sample is voluntarily found, and it’s a convenience sample.

Detached statistics

“One third fewer calories”… than what?

ambiguous averages

mean, median, mode, midrage, often not equal. a person can use one that best supports question.

changing the subject

“3% versus $6 million:

faulty survey questions

“Do you feel that statistics teachers should be paid higher salaries (good)” “Do you favor increasing tuiton so that colleges can pay statistic teacher higher salaries?(bad)”

confounding variable

variable that influences the outcome but not separated from independent variable (ex: allergies, environmental factors)