Variables and Distributions
Descriptive statistics
Samples
Hypotheses
Miscellaneous
100
An example of this kind of variable is the color of shirt that everyone in this room is wearing
What is categorical?
100
The type (level of measurement) of variable that we must have to calculate a mean.
What is quantitative?
100
We can make inferences about these, based on what we know about a sample.
What is the population or population parameter?
100
This is the probability of obtaining a test statistic at least as extreme as the one that was actually observed, assuming that the null hypothesis is true.
What is the p-value?
100
The technique we use when we want to estimate a population parameter from a sample statistic.
What is a confidence interval?
200
A variable to operationalize the concept of fatigue.
What is number of times yawned in an hour; many other answers are possible.
200
A way to graphically depict categorical data.
What is a pie chart or bar chart?
200
This is a list of individuals from which a sample is drawn.
What is the sampling frame?
200
The name we usually use for the standard deviation of the sampling distribution.
What is standard error?
200
Two sections of a class took the same quiz. Section A had 15 students who had a mean score of 80, and Section B had 20 students who had a mean score of 90. Overall, what was the mean score for all students on the quiz?
What is 85.7?
300
Among the following variables, this one is NOT quantitative: • age • test scores • religious denomination • daily high temperatures in December
What is religious denomination?
300
This is the percentage of observations within 2 standard deviations of the median, when we have a normal distribution.
What is 95%
300
Consider the following example: "An ABC News/Washington Post poll was conducted by landline and cell phone Jan. 29-Feb. 2, 2014, in English and Spanish, which included responses from a random national sample of 1,013 adults in the US. Fifty percent in an ABC News/Washington Post poll hold a favorable opinion of the Winter Olympics starting this week in Sochi, Russia." In this example, this is 1,013.
What is sample size?
300
According to a June 2004 Gallup poll, 28% of Americans “said there have been times in the last year when they haven’t been able to afford medical care.” Is this proportion higher for black Americans than for all Americans? In a random sample of 801 black Americans, 38% reported that there had been times in the last year when they had not been able to afford medical care. This is the number of tails you would use in a hypothesis test.
What is one-tailed, upper?
300
We use this technique when we want to compare the difference of a sample statistic from one sample with the parameter of a population
What is a one-sample hypothesis test?
400
Cleo’s scores are 98, 90, 93, 99, and 10 on the five assignments she submitted this semester in economics. This is the direction of the skew.
What is left?
400
When we have a normal distribution, a mean, and a standard deviation, this is the technique we use to calculate a percentile.
What is calculate a Z score?
400
I want to say something about all 22 students in this class. This is what we would call it if I collected data from all 22 students in the class.
What is a census?
400
A statistics professor wants to see if more than 80% of her students enjoyed taking her class. At the end of the term, she takes a random sample of students from her large class and asks, in an anonymous survey, if the students enjoyed taking her class. This hypothesis posits that p-hat = 0.80.
What is the null hypothesis?
400
A professor wants to know if her introductory statistics class has a good grasp of basic math. Six students are chosen at random from the class and given a math proficiency test. The professor wants the class to be able to score at least 70 on the test. The six students get scores of 62, 92, 75, 68, 83, and 95. Can the professor be at least 90 percent certain that the mean score for the class on the test would be at least 70? This is the null hypothesis (mindful of the number of tails).
What is mu < 70?
500
A quick and dirty indicator that we have a normal distribution.
What is median = mode?
500
A sample statistic we would expect to calculate for a quantitative variable.
What is the mean?
500
Suppose your local school district decides to randomly test high school students for attention deficit disorder (ADD). There are three high schools in the district, each with grades 9-12. The school board pools all of the students together and randomly samples 250 students. This is the type of sample.
What is a simple random sample?
500
In a one-sample hypothesis test, this is the value of the Z-statistic when p-hat = 0.49, n= 150, the benchmark is 0.55
What is 14.7?
500
An area hospital has received several complaints that hospital staff were responding too slowly to the emergency calls of senior citizens. The average wait time for a sample of 75 seniors was 5.5 minutes. The industry standard is 4.0 minutes. These are the null and alternative hypotheses (in symbols) to test whether this hospital meets the industry standard.
What are Null: mu = 4.0 Alternative: mu > 4.0
M
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