STATS 121 FINAL EXAM QUESTIONS WITH VERIFIED ANSWERS

STATS 121 FINAL EXAM QUESTIONS WITH VERIFIED
ANSWERS


x̄ - Answers - Sample mean

μ - Answers - 1. Population mean (parameter)
2. Mean of sampling distribution of
x̄

p - Answers - 1. Population proportion (parameter)
2. Mean of sampling distribution of p̂

p̂ - Answers - sample proportion

σ - Answers - Population standard deviation

s - Answers - Sample standard deviation, measures spread

t*(s/√n) - Answers - margin of error for estimating μ (±p̂ if categorical, x̄ if quantitative)

z*√(p̂(1-p̂)/n - Answers - margin of error for estimating p

σ/√n - Answers - Describe the standard deviation of the sampling distribution of x̄

s/√n - Answers - 1. standard error of the mean
2. estimates std. dev. of sampling distribution

√(p̂(1-p̂)/n) - Answers - standard error (dev) of p̂

Parameter vs. Statistic - Answers - We use a statistic to make inferences about a
parameter

When do I use a bar chart vs. Histogram - Answers - Bar Chart = categorical
Histogram = quantitative

5 number summary - Answers - Min, Q1, Median, Q3, Max

When do I use the mean or the median? - Answers - Use the median if outliers are
present

How does mean/median effect the skewness - Answers - Mean follows skewness
If skewed LEFT, mean is to the left of median
If skewed RIGHT, mean is right of median