Quant Exam 1

categorical & quantitative

2 types of data

categorical data

labels and names used to identify the attribute of an element

Quantitative data

consists of numbers that answer the question “how much” or “how many”

nominal & ordinal

Scales of measurement for categorical data

interval & ratio

Scale of measurement for quantitative data

nominal

scale of measurement where labels and names are used to identify the attribute of an element

ordinal

props of the nominal scale but Order matters

interval

props of the ordinal scale and difference between # matters. can only have whole numbers

ratio

props of interval scale but division is meaningful

categorical & nominal

type and scale: type of customer, gender, marital status

categorical & ordinal scale

type and scale: 1st, 2nd, 3rd place , Customer satisfaction: Unsatisfied, Neutral, Satisfied, Employee performance rating (Poor, Average, Good, Excellent), Shirt size → small, medium, large

quantitative & interval scale

type and scale: #of people, temperature , Year (2020, 2021, 2022)

quantitative & ratio

“per”, GPA, time, distance, weight, height, Number of sales ($0, $500, $1,000)

bar graph and pie chart

appropriate graphical representation for qualitative/ categorical data

histogram

appropriate graphical representation for quantitative data

population mean

μ

sample mean

x̄

population variance

σ²

sample variance

s²

population standard deviation

σ

sample standard deviation

s

population proportion

p

sample proportion

p̂

population parameter

whole population

sample statistic

sample/ subset of population

mean

measure of the middle, influenced by extreme values

median

middle # in dataset

mode

most frequently occurring # in the data set

range

largest # in dataset - smallest # in dataset *most influenced by extreme values

standard deviation

square root of the variance

iqr

range of the middle 50% of data —> = Q3- Q1

outlier

any data point below LL or above UL

limits

is it an extreme value or an outlier

mean, standard error, normally distributed

3 parts of sampling distribution

finite

random sample from _____population : each individual has an equal likelyhood of being selected

infinite

random sample from an _____population: make sure everyone is a member of population, each person selected independently

stratified random sampling

divides the population into subgroups based on specific characteristics and take proportional # from population

cluster

sample everyone from one location (street blocK)

systematic sampling

sample every 2, 10, 50 people. some system of when the survey is given

bigger sample size

with non-probabilistic sampling, you need a ___ ___ ___ to avoid bias

convivence sampling

people you just run into

judgment sampling

ask expert who you should sample- they know a lot about topic you are researching

confidence interval and hypothesis testing

statistical methods to prove there is not a significant difference between the population parameter and the point estimate

confidence interval formula

point estimator +- test statistic x standard error

increased, increased moe, increased confidence

_____ interval → ___ ___ → ____ ____

width, increased, margin of error increased

as the confidence level is increased… the ____ of the confidence interval ____ and the ___ __ ___ _____