Sampling Methods
This sampling method gives every member of the population an equal chance of being selected. What kind of sample is this?
Random sample
A graph that shows frequencies for categories by using rectangular bars.
A bar graph
What is the null hypothesis?
A statement assuming no relationship or difference exists between two variables.
What is the sample mean?
the average of a small, randomly selected group taken from a larger population
What is the percentage chance of flipping a fair coin and landing on tails?
50%
What is sampling bias?
a sample that does not fairly represent the population.
this graph displays continuous data grouped into intervals with no gaps between the rectangles.
A Histogram
What is p-value?
a statistical measurement used to determine if your results are real or just happened by chance
What is a confidence interval?
A confidence interval calculates a range of values likely to contain a population parameter (like a mean or proportion) with a specified level of confidence.
True or false: the probability of rolling an even number on a standard die is 50%
True. Three of the six numbers are even (2, 4, 6), which simplifies to half.
What is convenience sampling?
Convenience sampling means choosing participants simply because they are the easiest to reach.
A bell-shaped curve where the mean, median, and mode are all located at the exact center of the data.
A normal distribution
When the p-value is less than alpha what do you do to the null hypothesis?
reject the null hypothesis
What does a 95% confidence level mean?
A 95% confidence level means that if we repeated the sampling process many times, about 95% of the constructed confidence intervals would contain the true population parameter.
If 500 people buy exactly one raffle ticket each, and there is only one winning prize, what is your chance of winning if you bought one ticket?
1 out of 500
What is a non response?
Non-response happens when selected participants cannot be contacted, choose to ignore a survey, or refuse to answer specific questions
On a boxplot, this specific visual element represents the distance between the first quartile and the third quartile
The box
Rejecting a true null hypothesis is what type of error?
Type 1 error
True or False: A 95% confidence interval means there is a 95% probability that the true population mean lies inside that specific calculated interval.
False. A 95% confidence interval does not mean there is a 95% probability that the true population mean lies inside that specific calculated interval.
You roll two dice at the same time. What is the lowest total sum you can possibly get?
2, The lowest roll on each individual die is a 1
What is cluster sampling?
When a population is divided into groups and we randomly select entire groups to participate in our study, rather than pulling individuals from every group.
What graph uses the five-number summary?
Box-and-whisker plot
When a researcher fails to reject a false null hypothesis its called a...
False negative
What is the margin of error?
Statistic that expresses the amount of random sampling error in a survey's or study's results
True or false: If you flip a coin 5 times and get Heads every time, the 6th flip is more likely to be Tails.
False. The coin has no memory. Each flip is always a 50/50 chance.