Data Talk
Which measure of the center is heavily affected by outliers?
Medians
What is a simple random sample?
A sample where every possible sample of the same size has an equal chance of being selected.
What is the probability of rolling a 3 on a fair six-sided die?
1/6
What does a confidence interval estimate?
A population parameter
What is the null hypothesis?
The claim of no effect or no difference.
What do we call a distribution with a long tail on the right side?
Skewed right
What is the difference between a population and a sample?
Population = entire group; Sample = subset of the population studied.
What is the probability of getting exactly one head in two coin flips?
1/2
If sample size increases, what happens to the margin of error?
It decreases
What is a p-value?
The probability of obtaining results as extreme as those observed if the null hypothesis is true
What graph is commonly used to identify outliers using the 1.5 × IQR rule?
Boxplot
Why is random assignment used in experiments?
To create comparable groups and allow cause-and-effect conclusions.
two events are independent, how do you find P(A and B)?
Multiply the probabilities
Which interval is wider: 90% or 99%?
99%
If p-value < α, what decision should be made?
Reject the null hypothesis.
A dataset has Q1 = 12 and Q3 = 20. What is the IQR?
8
In a double-blind study, who does not know which treatment is received?
Both subjects and researchers.
A fair coin is flipped 3 times. What is the probability of getting all heads?
1/8
A 95% confidence interval is (42, 50). What is the point estimate?
46
What is a Type I error?
Rejecting a true null hypothesis When we shouldnt have
A distribution is strongly skewed left. Which measures of center and spread should be reported?
Median and IQR
A survey asks viewers of a news channel to call in and vote on an issue. What type of bias is likely present?
Voluntary response bias.
A fair die is rolled twice. What is the probability that both rolls are even?
1/4
A confidence interval for a population mean is (18, 24). What is the margin of error?
3
study reports a p-value of 0.04. Whats a correct conclusion at α = 0.05?
We reject the null hypothesis because there is convincing evidence in favor of the alternative hypothesis.