Questions and Answers
A sample from a population should be which of the following?
Which of the following is not a characteristic of predictive modeling?
The standard error measures the variability associated with the sample mean, x̄.
True
Select the statement below that incorrectly interprets a 95% confidence interval (15.02, 15.04) for the population mean, if the sample mean is 15.03 ounces.
Signup and view all the answers
How do you define the term power?
Signup and view all the answers
The location and spread of a normal distribution depend on the value of which two parameters?
Signup and view all the answers
What type of error did the bank manager make if he concluded that the loan error rate was above 1% when in reality it is not?
Signup and view all the answers
To reject a test with Student's t statistic, the t statistic should be far from 0 and have a small corresponding p-value.
Signup and view all the answers
Which PROC TTEST option would you use to change the confidence level in a confidence interval plot?
Signup and view all the answers
A CLASS statement is required in a two-sample t test.
Signup and view all the answers
You can examine Levene's test for homogeneity to more formally test which of the following assumptions?
Signup and view all the answers
Given the following output, is there sufficient evidence to reject the assumption of equal variances?
Signup and view all the answers
Given the following SAS output, is there sufficient evidence to reject the hypothesis of equal means?
Signup and view all the answers
Study Notes
Sample and Representativeness
- A sample from a population must be representative to ensure accurate results in statistical analysis.
Predictive Modeling
- Predictive modeling addresses relationships between variables, but does not simply answer "How is X related to Y?"
Standard Error
- The standard error quantifies the variability associated with the sample mean (x̄); it reflects how much the sample mean would vary from the true population mean.
Confidence Intervals
- Misinterpretation of a 95% confidence interval involves thinking there is a 0.95 probability that the true mean lies within the interval; this is incorrect.
Statistical Power
- Power is defined as the measure of a statistical test's ability to correctly reject the null hypothesis when it is false, indicating the effectiveness of the test.
Normal Distribution Parameters
- The location and spread of a normal distribution are determined by two parameters: the mean (μ) and the standard deviation (σ).
Type I Error
- A Type I error occurs when a bank manager concludes that the loan error rate exceeds 1%, despite it being correct that it does not.
Student's t Test
- To reject a null hypothesis in a t-test, the t-statistic must be significantly far from 0, accompanied by a small p-value.
PROC TTEST ALPHA Option
- The ALPHA= option in PROC TTEST is used to adjust the confidence level for confidence interval plots.
CLASS Statement in T-tests
- A CLASS statement is required when conducting a two-sample t-test to categorize the data properly.
Levene's Test for Homogeneity
- Levene's test is used to formally evaluate the assumption of equal variances among groups in statistical analyses.
Evidence Against Equal Variances
- Analysis from Levene's Test indicates insufficient evidence to reject the assumption of equal variances if the p-value is above the significance level (e.g., 0.05).
Hypothesis Testing with SAS Output
- To determine whether there is enough evidence to reject the null hypothesis of equal means, analyze the F value and corresponding p-value from the provided SAS output.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge with these SAS flashcards focused on key statistical concepts. Challenge yourself with definitions, characteristics of predictive modeling, and interpretations of statistical measures. Perfect for students and professionals looking to reinforce their understanding of statistics using SAS.
