statistics and probability (newest). everything i need to know

Sample surveys

A _____ are composed of randomly selected answers from larger surveys.

You can’t draw inferences with these , but you can draw generalizations based on the experimenters results.

Observational study

The experimenter simply looks at something already happening.

it is a nonrandom_ selection

you can find causation for the sample studied.

it is also cost effective.

There’s causation but no generalization

It’s just on the observed population no world population.

Controlled experiments

The populations are randomly assigned to treatment groups.

They can be randomly selected

They can lead to an inference or generalization, but generalization can only happen if it is a random selection (randomly selected is mostly what I mean) otherwise there’s a risk of potential bias.

single blind study = the subject is ____ of their treatment

They also don’t know what side they’re on.

Unaware.

eliminates SOME bias

Double blind study

The experimenter and the subject are unaware until the results are revealed.

Eliminates bias for the most part.

Characteristics of quality studies

A ____ assignment of treatments

A large ___ of subjects and participatants

There’s __ of comparisoon group

random

Number

Control

Generalization

applying the findings from a study to a larger group or situation beyond the specific participants or context of the study.

Normal distribution curves are ___

Symmetrical

68%

1 sd from mean

95%

2 SD of mean

99.7%

3 SD of the mean

if you’re given a specific individual and need to find the percentile that it represents, what do you use on the calculator

The normal cdf function

Confidence intervals

Measures how good the data is.

Formula for confidence intervals

Margin of error!!

This special term in statistics is greater when there are less people.

Double tap the image if you have a hard time seeing!!

If you have a low margin of error that means you have a

High sample size

Random samples

The members of a population are equally likely to be chosen.

• survey was given to everyone who is selected by a random number generator

Random samples are un_____

Unbiased

Systematic sample

These samples order the population in some way, then select it for regular intervals.

• a survey is given to every 5th person who enters a mall. (Type of random sample as well)

Systematic samples are un___

Unbiased

Convenience sample

Selecting any members of the population who are conveniently and readily available.

example: a survey is given only to the friends and family of the researcher

Convenience samples are ____

Biased

Volunteer sample

These samples only select members of a population who volunteer.

• a survey is left on a table in the mall to be done by those who volunteer.

Volunteer samples are ___

Biased!!

Simulation

when you model a real-world random process using random numbers or technology to estimate probabilities or outcomes.