Questions and Answers
What type of analysis should Mike use to compare the GPA between freshmen, sophomores, juniors, and seniors?
one-way ANOVA
What type of analysis should Mike use after regrouping his participants into upperclassmen and lowerclassmen?
t-test
Moa's experiment on employee productivity is a ___ design.
between participant, quasi-experimental design
What is the median and mode of your last test with an average of 70 and a normal distribution?
Signup and view all the answers
What was your grade if your z-score was +2 with an average of 70 and standard deviation of 10?
Signup and view all the answers
What percentage of your class scored between 60 and 80 if the standard deviation is 10 and the average is 70?
Signup and view all the answers
What is your friend's z-score if they scored 55 with an average of 50 and a standard deviation of 10?
Signup and view all the answers
What score does a z of 0 correspond to if the average is 50?
Signup and view all the answers
95% of the people get between ___ and ___ dates based on an average of 5 with a standard deviation of 1.
Signup and view all the answers
What happens to the interval when changing from a 95% confidence interval to a 99% confidence interval?
Signup and view all the answers
What happens to the 95% confidence interval when increasing the sample size from n=50 to n=5000?
Signup and view all the answers
According to the Central Limit Theorem, what happens to the mean of the sample as the sample size increases?
Signup and view all the answers
What happens to the variability of the distribution of sample means if the sample size increases?
Signup and view all the answers
According to the Central Limit Theorem, what happens to the shape of the sample as the sample size increases?
Signup and view all the answers
What can be expected about the shape of the sampling distribution of sample means if the sample size goes from 5 to 10,000?
Signup and view all the answers
How are the variance and the standard deviation different?
Signup and view all the answers
How are the variance and the standard deviation related?
Signup and view all the answers
If you scored an IQ of 130, what would your z-score be if the mean is 100 and standard deviation is 15?
Signup and view all the answers
What z-score best corresponds to a test score at the 50th percentile?
Signup and view all the answers
Which analysis should your professor use to predict your GPA based on the number of classes you take?
Signup and view all the answers
What analysis is used in a study comparing the tip percentage between two groups?
Signup and view all the answers
68% of all pizza delivery times range between ___ and ___.
Signup and view all the answers
If you scored an IQ of 122.5, what would your z-score be?
Signup and view all the answers
What does the graph show regarding the central limit theorem?
Signup and view all the answers
What is a z-score?
Signup and view all the answers
Study Notes
Analysis Types
- One-way ANOVA is used to compare the GPA across multiple groups, such as freshmen, sophomores, juniors, and seniors.
- A t-test is appropriate for comparing the GPA between two groups, like upperclassmen and lowerclassmen.
Experimental Design
- A between-participant, quasi-experimental design measures productivity differences between employees working different schedules (10 hour days vs. 8 hour days).
Statistical Data
- In a normally distributed test scoring, both the median and mode are equal to the average score, which is 70.
- A z-score of +2 corresponds to a grade of 90 when the test mean is 70 and the standard deviation is 10.
Percentile and Standard Deviation
- Approximately 68.26% of scores fall within one standard deviation (60-80) from the mean in a normal distribution.
- A z-score calculates the position of a score in relation to the mean, with a +0.5 indicating a score of 55 in a test with a mean of 50.
Confidence Intervals
- Changing a confidence interval from 95% to 99% results in a wider range due to increased uncertainty.
- Increasing sample size from n=50 to n=5000 narrows the confidence interval, improving precision.
Central Limit Theorem
- With an increased sample size, the sample mean tends closer to the population mean, and the variability of sample means decreases.
- As sample size grows, the distribution of sample means approaches a normal shape, even if the parent population is skewed.
Variance and Standard Deviation
- Variance represents the average of squared deviations from the mean and is typically larger than standard deviation.
- Standard deviation is the square root of the variance.
IQ Scores and Percentiles
- An IQ of 130 corresponds to a z-score of 2, while an IQ of 122.5 corresponds to a z-score of 1.5.
- Scoring at the 50th percentile corresponds to a z-score of 0, indicating an average performance.
Predictive Analysis
- Regression analysis is used to predict outcomes, such as GPA based on the number of classes taken.
Testing and Percentages
- A study comparing tip percentages between groups receiving chocolate versus those who don't is analyzed with a t-test.
- In a pizza delivery time distribution with a mean of 30 minutes and standard deviation of 5 minutes, 68% of delivery times fall between 25 and 35 minutes.
Z-score Definition
- A z-score measures how many standard deviations a score deviates from the mean, providing context for an individual score within a distribution.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on various statistical analysis types, including ANOVA, t-tests, and z-scores. This quiz covers experimental design and key concepts such as confidence intervals and standard deviations. Ideal for students looking to solidify their understanding of statistics.
