Sampling randomly (carefully)
Type of sample that gives everyone in a population an equal chance of being selected for the sample.
What is a random sample?
You ask one person who has mud wrestled to respond to your survey and ask them to suggest other mud wrestlers who might be willing to respond to your survey.
Percent of people below a person who is in the 67th percentile
What is 67 percent?
What is 'normal?'
The purpose of a confidence interval
What is: Use a sample mean to estimate a population mean (also need standard error)
A sample selects every 20th person on a list of everyone in the sampling frame.
What is a systematic random sample?
You hang out at a health fair in a local park and ask people if they will respond to your survey about the COVID vaccine.
What is a convenience sample?
The percentile of the median
What is the 50th percentile?
True or false: A normal curve is not so different from a histogram that has a symmetric, bell-shape
1.96
What is the number of units of standard error needed to create a 95% confidence interval?
Chance of being selected for a simple random sample if there are 500 people in the population and the sample will be 50 people?
What is 1 in 10, or .10 or 10%?
You get permission to survey people outside a pet store to ask people how they cope when their pet is ill.
What is a convenience sample?
Percent of people whose value is above a person who is in the 85th percentile?
What is 15%
What is 'standard error?'
Standard error if n = 100 and standard deviation = 63
What is 6.3
Sample type that decides on groupings in the population and groups people before randomly sampling from each group
Stratified random sampling
You figure out who you should talk to in order to get an accurate picture of a local planning issue.
What is a purposive sample?
True or false: Sometimes a percentile captures a percent both below and above a given value.
False; percentile is, by definition, the portion or percentage below a given value.
Which is larger, the mean of the sample means or the population mean? (Might be a trick question.)
The percentage of possible pop. means included in c 90% confidence interval.
90% of them
The two ways (generally speaking) that the number of people in each strata (group) of a stratified random sample can be determined.
Proportional (to the population) and disproportional
Which is the best, a convenience sample, a purposive sample, or a snowball sample? (might be a trick question)
The best type of sample is the one that will help get good data to answer a question. None of these are necessary better than the others.
The percentile you would like to be in for the 'number of close friends.'
No wrong answer!
What is population standard deviation divided by the square root of the sample size?