MATH130 - Statistics Midterm 1 Study Guide (VOCAB ONLY)

qualitative data

describes qualities/characteristics not numbers

quantitative data

describes amounts/measurable things and is numerical

discrete data

numerical data values that can be COUNTED

continuous Data

data measured on a scale and can be broken into smaller parts

observational study

observed study and measures variables of interest but does not influence a response

experimental study

giving treatment to a group and observing a response out of them to study whether treatment has an impact

component that makes an observational study stronger

1. good sampling design

2. description of methodologies and use of multiple means

3. academic and trustworthy data analysis

4. discussion of weaknesses

5. verbiage/design of study

6. comparison groups when necessary

7. avoidance of simpsons paradox

cofounding variable

variable that researchers aren't intentionally testing/taking conclusions on

convenience sampling

using a sample of people who are readily available to participate + easy to reach

voluntary response sampling

lets individuals choose to participate or not

undercoverage bias

happens when individuals cannot be reached/refuse to participate in a survey

response bias

anything in a survey design that influences responses + bias

nonresponse bias

bias introduced to a sample when a large fraction of those sampled fails to respond

simple random sample

every member of the population has a known and equal chance of selection

stratified random sample

a sample from selected subgroups of the target population in which everyone in those subgroups has an equal chance of being included in the research

multistate sample

sampling schemes that combine several sampling methods, commonly used by government

randomization

the assigning of subjects randomly to both experimental and control groups

double-blind experiment

an experiment in which neither the experimenter nor the participants know which participants received which treatment

replicable

experiment that can be repeated by other researchers and get same results

controlled experiment

experiment in which only one variable is manipulated at a time

blind study

participants are not told whether they're in the control or experiment group

placebo

something which has a positive mental effect, but no physical effect

placebo effect

when participants experience changes bc they believe they are receiving treatment

extrapolation

Estimating a value outside the range of measured data.

when to use mean and standard deviation

data is symmetrical (not skewed), no outliers, looking at the average and how much values vary around it

when to use five-number summary

the data is skewed or has outliers, want to understand the spread and center of the data

mean

average

median

the middle score in a distribution; half the scores are above it and half are below it

when to use bar graph

use for: qualitative (categorical) data

shows: counts or frequencies for each category

bars are separate

when to use histogram

use for: quantitative, continuous data

shows: how data is grouped into intervals (bins)

bars touch

when to use pi chart

use for: qualitative (categorical) data

shows: parts of a whole as percentages

best when you want to show proportions

when to use time plot

use for: quantitative data over time

shows: trends or patterns

when to use a stem and leaf plot

use for: Small sets of quantitative data

shows: actual data values & distribution

right skew

mean is greater than median

left skew

mean is less than median

control group

the group that does not receive the experimental treatment.

treatment group

the group that receives the treatment

response variable

measures an outcome of a study