Exploring Data
What graph is used to show the distribution of quantitative data using intervals (bins) and frequency?
Histogram
What sampling method divides the population into groups by characteristic then randomly samples within each group?
Stratified random sampling
What are the four conditions for a binomial distribution (BINS)?
Binary, Independent, Number fixed, Same probability
What condition is required for the Central Limit Theorem (CLT) for sample means?
n ≥ 30 (or population normal)
What does the null hypothesis H₀ usually represent?
No effect / No difference / No association
What are the three common measures of center in a data set?
Mean, Median, Mode
What type of study randomly assigns treatments to compare groups and establishes causation?
Experiment
What is the formula for the mean of a binomial distribution?
μ = np
What is the formula for the standard error of a sample proportion?
√(p̂(1 – p̂)/n)
At α = 0.05, what decision do you make if p-value ≤ 0.05?
Reject H₀
What formula is used to identify outliers in a boxplot?
Q1 – 1.5×IQR and Q3 + 1.5×IQR
What type of bias occurs when researchers choose easily accessible subjects?
Convenience bias
State the general addition rule: P(A or B)
P(A) + P(B) – P(A and B)
As sample size increases, what happens to the standard deviation of the sample mean?
It decreases
What error occurs when you reject a true null hypothesis?
Type I error
What is the range of the correlation coefficient r, and what does the sign indicate?
–1 ≤ r ≤ 1; sign indicates positive or negative linear association
What experimental design keeps both subjects and researchers unaware of treatment groups?
Double-blind experiment
What intervals does the 68–95–99.7 rule use for normal distributions?
±1σ, ±2σ, ±3σ from the mean
What distribution is used for one-sample mean inference when σ is unknown?
t-distribution
What test compares the means of three or more groups?
ANOVA (Analysis of Variance)
What does the coefficient of determination r² represent?
The proportion of variation in y explained by the linear model with x
What sampling method divides the population into clusters, randomly selects clusters, and surveys everyone in selected clusters?
Cluster sampling
What distribution models the count of rare events in a fixed interval?
Poisson distribution
What is the purpose of the 10% condition in sampling?
To ensure independence when sampling without replacement
What is the correct interpretation of a 95% confidence interval?
About 95% of intervals from repeated samples would capture the true population parameter