U_5 Check for Understand

Creating a hypothesis

A theory or statements that is accepted or refuted

(if…else)

Opposite Hypothesis

invalid hypotheses that says variables are related

(two if..else statements, only one variable changes)

Example of the opposite Hypothesis based on age of class size

i.e. More than half of the class is 13

More than half of the class is not 13

Primary Data

Orignal data that a researcher gathers specifcially for an experiment/survey

Secondart Data

Data that someone else has already gathered for a specific purpose

Population

The whole group of people/items

Simple Random Sample

Each person has equal chance of being choses

An example of a simple Random Sample

pulling names from a hat

What is the definition of a Systematic Random sample?

Choosing a specified number of people from a population at fixed intervals

What is an example of a Systematic random sample

choose every 10th person on a list of MS names from a random starting point

What is the defintion of a stratified random sample?

A population is divided into distinct groups and proportional sample selected from each group (each group has 10% taken from population)

What is an example of a stratified random sample (using the middle school)?

Dividing MS into grades and taking 10% of each population

Non-random Sampling

participants aren’t selected randomly

What are the cons of non -randoming sampling?

Not everyone gets an equal chance

not everyone is fully represented

What are the cons of non -randoming sampling?

You can choose who you want

Bias

unrepresented data (error from choosing a sample that doesn’t represented the whole population)

Mean

the average of a set of numbers

How to find the mean?

Add together all of the numbers and divide by how many numbers that there are

Mode

is the data value that occurs most often in the set

Median

the middle number of a number set that is in ascending order

How to find median in an odd number set?

Put numbers in ascending order and cut it in half

How to find a median in an even number set?

After cutting it find the average of the middle number

What is the range?

The difference between the highest and lowest numbers

How to find the range?

Subtract the biggest number from the smallest number (i.e. biggest # = 32, smallest # = 2, range = 30)

What is an Independent Variable

A variable that affects the value of another variable

What is a dependent variable

A variable that is affected by another variable

What is an Outlier?

A measurement that is different from the rest of the data very significantly

Census

If you ask everyone in the entire population

What does a scatterplot allow us to do?

Allows us to see if there’s a relationship between two set of data

What is an inference?

A conclusion based on reasoning and data

What does a linear relationship mean?

Means that the 2 variables form a straight line

What does a non-linear relationship mean?

A relationship that doesn’t form a straight line when graphed

What is a trend?

A pattern to the data (either upward or downward)

What is line of best fit?

A straight line that comes closest to points on a scatterplot (Same number of points above and below)

What does it mean to interpolate?

Estimate a value between to measurements in a data set

What does it mean to extrapolate?

Estimate a value beyond the graph using a line of best fit

Positive correlation

A relationship between 2 variables that move together (when dependent increases, independent increases)

Negative Correlation

A relationship between 2 variables that move in opposite direction (independent increases, dependent decreases)