Vocabulary & Concepts
What is the average of a data set called?
Mean
A fair coin is flipped once. What is the probability of heads?
1/2 or 50%
Which graph is best for showing the relationship between two quantitative variables?
Scatterplot
What is the purpose of random assignment in an experiment?
To remove/reduce bias
If a p-value is less than 0.05, what do we do with the null hypothesis?
Reject the null hypothesis.
What measure of center is the middle value in a data set?
Median
A bag contains 4 red marbles and 6 blue marbles. What is the probability of drawing a red marble?
0.4 or 40%
Which graph is best for displaying categorical data?
Bar graph
What is the population in a statistical study?
The entire group of interest.
What is the purpose of a confidence interval?
To estimate a population parameter.
What is an outlier?
A value that is unusually far from the rest of the data.
A die is rolled. What is the probability of getting an even number?
1/2 or 50%
A histogram is skewed left. Which side has the longer tail?
Left side
What is a sample?
A subset of the population.
A 95% confidence interval for a mean is (20, 30). What is the midpoint?
25
What does standard deviation measure?
The spread of a data set.
A coin is flipped twice. What is the probability of getting two heads?
1/4
In a scatterplot, what does a downward trend indicate?
Negative association
Why do statisticians prefer random samples?
They reduce bias.
What does a small p-value suggest?
Evidence against the null hypothesis.
Which measure of center is most resistant to outliers?
Median
If P(A)=0.5 and P(B)=0.3 and the events are independent, find P(A and B).
0.15
A boxplot shows a point beyond the whiskers. What does that point likely represent?
An outlier
In an experiment, what is the treatment?
The condition applied to subjects.
If a p-value is 0.08 and α = 0.05, what decision should be made?
Fail to reject the null hypothesis.