Mystery
What are the symbols for the standard deviation of samples?
What about the population?
s for sample, sigma for population
How do you interpret boxplots when used to assume normality?
Somewhat symmetric
10 years ago, a random sample of 500 voting citizens of Anderson County showed that 39% of voters believe that our roads should be better maintained. A random sample of 1000 voting citizens in recent years showed that 48% of voters believed our roads should be better maintained. Does the data indicate an increase in the opinion that roads in Anderson County are crappy? What are the null and alternative hypotheses?
Ho: p1 - p2 = 0
Ha: p1 - p2 < 0
If the confidence interval contains zero, is there a significant difference between the two groups of data?
No
When both integers of an interval are negative which group would have a mean or proportion that is larger?
The second group
p-val = .0002
alpha = .05
What is the interpretation?
Reject the Ho
When are boxplots used in two sample tests and intervals?
When you are given raw data
Define a 95% confidence level
In repeated sampling, 95% of the intervals formed will contain the true population mean
What does the p-value determine?
Determines whether the null hypothesis is rejected or failed to reject
10 years ago, a random sample of 500 voting citizens of Anderson County showed that 39% of voters believe that our roads should be better maintained. A random sample of 1000 voting citizens in recent years showed that 48% of voters believed our roads should be better maintained. Does the data indicate an increase in the opinion that roads in Anderson County are crappy? Considering all assumptions are met, find the p-value.
p-value = .0005
How would you make a conclusion for a 99% confidence interval?
We are 99% confident that the (parameter) is between _____ and ______ (interval). *Use context*
What are the assumptions for matched pairs?
- Dependent Random Samples
- Approximately Normal