# averages

1. ### Help explaining why question averages don't sum to composite score average

Hi all, For context, I've inherited a report that uses an average of averages to compute a composite score. Data was collected from a survey where three composite scores are calculated for three separate dimensions. For example, Composite Score 1 has 5 questions associated with it. Each...
2. ### Comparison of averages

Hi, I'm hoping this is a very basic question for someone. I am comparing some statistics from a private language school over two years: In one year there were 120 classes with an average of 7.3 students per class In the second year there were 140 classes with an average of 9.5 students...
3. ### Regression with averaged data

I have data that represents the average for a group, which I would like to use for my response variable. I have different variables that are collected about my groups, and would like to predict the average using a linear model. While the usual assumptions don't hold for the individual data (and...
4. ### Stata Unbalanced Panel Data - which ttest should I use to compare means?

Hi, Apologies if this question is very basic but I have spent hours looking online and in forums such as this one for an answer and I am still unsure. I have an unbalanced panel data set of a few thousand firms, for the years 2002 to 2008. I have looked at the mean values for the audit...
5. ### How to analyze statistical difference between averages of mode, mean and median?

Attached is the graph with my data: I have 4 distributions of particles of different sizes. For each one of them, a particle size frequency distribution has been measured three times. Median, mean and mode were calculated for each frequency distribution and averaged for each of the four...
6. ### Performing a t-test on averages??

Is it "statistically legal" to perform a t-test on the averages of two groups? In other words, the data set values are averages themselves (example: a ttest performed on GPAs). I realize that doing a ttest on averages is pretty much like taking the average of averages, which is in most cases a...