Proportions
When is an alternate hypothesis one-sided?
If the parameter is greater than or less than the null value
i.e. Ha = p > < Ho
What calculator function or other resource can you use to find the critical value for a t-interval?
invT or Table B
Which chi-squared test allows us to determine whether a hypothesized distribution seems valid?
chi-square goodness-of-fit-test
What are the assumptions/conditions you must check for TWO-proportion tests?
Randomness, independence, sample size, and independent groups
What is the formula for a confidence interval of a proportion test?
statistic +/- critical value (standard error)
What is the critical value for a 99% confidence interval?
2.575
When is there statistically significant evidence for confidence intervals?
If 0 is not on the interval
How many degrees of freedom are there for a chi-squared goodness of fit test with 8?
df = 7
What is a type II error?
Failed to reject the null hypothesis, but it was false
What is the formula for degrees of freedom of a chi-squared GOF test?
number of categories - 1
What does a 95% confidence interval mean generally?
95% of samples of this size will produce confidence intervals that contain the
true proportion.
What is the difference between the difference of means and mean difference?
Difference of means is the difference of averages between two independent groups, mean difference is the difference between data within the same group
Which chi-squared test checks whether or not two variables are likely to be related or not?
Chi-squared test of independence
What is type I error?
Reject null but true
What is the formula for degrees of freedom of a chi-squared test for homogeneity?
df = (rows-1)(columns-1)
For hypothesis testing do you use the sample proportion or the population proportion?
Population proportion
What is the difference between the normal model a t-distribution?
the tails are fatter, larger variance
Which chi-squared test allows us to determine whether different columns/rows of data in a table come from the same population?
Chi-squared test of homogeneity.
What does increasing the confidence interval do?
Makes the interval wider, but the results are less precise
What is the formula for a confidence interval to estimate the slope of a regression equation?
CI = b1 +/- t*(n-2) SE (b1)
How can one increase the power of the test?
Increasing the sample size and increasing the alpha value
What is the benefit of pooling data?
There are more degrees of freedom
Which chi-squared test allows us to determine whether different columns/rows of data in a table come from the same population?
Chi-squared test of homogeneity
What is the additional condition you must check if you want to pool data?
Similar spreads condition - the pooled data must have similar variances
What is the formula for the chi-squared statistic?
x^2 = (sum) (Observed-Expected)^2/Expected