Random Problems
People are trying to find how many kids like pizza. They ask 1 out of every 3 kids they see. What type of sample is this?
What is a systematic random sample?
entire group of individuals we want information about
What is Population?
Everyone who enters a local ice-cream shop is selected for a survey asking people if they like ice-cream. Will this survey have bias in it? If so what kind?
Yes, under-coverage bias
The z-score for a 90% Confidence Interval
What z=1.645
What is a survey?
What is a question you are asking a group of people?
You are trying to see how many people have been running in the last week. They make you do the survey when you go into the super market. The machine picks 30 people at random. Is this sample fair?
What is yes?
The elements of the population are put into a list and every n-th element in the list are chosen for the sample
What is systematic sample
Every 7th person that enters King Soopers is asked what their favorite pizza topping is. Will this survey have bias in it? If so what kind?
What is no
The z-score for a 95% Confidence Interval
What is z= 1.96
What is a sample?
What is a small group of people to represent a larger group of people in a survey?
If you play Eny Meny Miny Mo starting with the same people starting on the same person, is that random?
What is no?
a treatment know to have no effect
What is a placebo?
People are randomly selected for a survey. They are asked "Do you agree that students should be given less homework?" Will this survey have bias in it? If so what kind?
What is yes, response bias
The z-score for a 99% Confidence Interval
What is z= 2.576
What is a treatment?
What is the process applied to randomly assigned experimental units?
You go to the Breckenridge ski area parking lot and you get selected for a survey. They say," You are the 10th person to come in. They ask you if Breck is your favorite ski area. What type of sample is this?
What is a systematic sample?
when every individual in both groups of people that can affect the outcome of an experiment are blinded
What is double blind?
You post a link to a survey on social media and ask for people to respond and share it with others. Will this survey have bias in it? If so what kind?
What is yes, multiple types including under coverage, volunteer response, and non response?
The formula for a Confidence Interval
x +/- z * s/sqrt n
What is statistically significant
What is When an observed difference is too large for us to believe that it is likely to have occurred by chance?
A computer randomly selects you to be part of a survey. Why is this a simple random sample?
What is this is a simple random sample because you were randomly selected, not selected on purpose.
an observational study in which subjects are selected and then their previous conditions or behaviors are determined
What is retrospective study?
When performing an experiment what things do we want to do to prevent all types of bias.
What is randomize, double blind, and placebo controlled.
If the sample mean is 40 from a sample of 100 people with a standard deviation of 16.2 what is a 95% confidence interval?
what is (36.8, 43.2)
What is a Cluster Sample?
What when only selective subgroups questioned, not everybody?