# average

1. ### Averaging rows from a matrix

I'm fairly new to using R, and wonder if someone could give me some help subsetting large data matrices in specific ways. I've attached a data file. It measures the percent of light reflected off of plants at 2048 different wavelengths. The first column is wavelength, which ranges from 339.99...
2. ### How does having samples of value = zero affect the average of a sample size?

Question: a store has an average of 500 customers a day, from a sample of 56 days of data. How many days can have a measure of zero customers while keeping withing +/-5% of the average? I'm not sure what data i need to collect or if i can calculate this based on the above information only...
3. ### Comparison of average values of data sets

Hi, I want to know if mean of A>B and A1, A2 are the two subsets of A. Similarily, B1, B2 are two subsets of B. Is the condition A1<B1 and A2<B2 mathematically possible????? As I think it is not. I think that either both or at least one subset must have shown the same relationship in their...
4. ### Averages of sales analysis

Hi! I've conducted an experiment in a supermarket with music in which I had 3 situations: 1. No music 2. Soft music 3. Loud music I changed the situation every 3 hours during 6 days. Now the problem is that I did not recieve the right data from the manager. I wanted to get all of the...
5. ### The avarage age problem

Hi Guys, I’m trying to figure out a good model for modeling the average age of a population. More specifically the average number of years people have been enrolled at a university who are in turn members of a club, which I call “age”. • The rate at which new members arrive could be...
6. ### average p values???

I have to compare demographics of a study that was s . In the "pre" group, I have 385 patients, in the post group, I have 317 patients. No patients are the same; I also took all of their ethnicities and compiled it into my MS excel spread via 0, 1, 2, 3...

Hello , I started a Statistics class a few weeks ago and i'm still pretty lost. Could someone explain to me how I should resolve this following problem ? Please. On the math SAT taken in 1994, the average score for men was 500 and the average score for women was 460. The histograms for...
8. ### Calculating the average variance of several normal distributed variables

Hi, I have the following problem. I'm trying to average several normal distributed variables. To make it more easy, I'm using z-scores. The mean of the average is (Mx1 + Mx2 + Mx3)/3, in this case 0. But how do you calculate the variance? If I assume they are independent, am I...
9. ### Utilizing Individual Data Points in an ANOVA, Reliability, Replication

Hi all. Suppose you are conducting a study with n=10 subjects. Each subject runs through a behavioural experiment for treatment A and treatment B, and several data points are collected. Before conducting the ANOVA, an AVERAGE score is calculated for each subject based on all their...
10. ### Help on Ratio

Can anyone help me? For example, I have a store, 4 people bought iPhones and each buyer bought accessories too. Buyer#1: 1 iPhone, 4 accessories Buyer#2: 2 iPhone, 6 accessories Buyer#3: 2 iPhone, 4 accessories Buyer#4: 4 iPhone, 9 accessories What is correct: 1. The Ratio of...
11. ### Uncertainty in Standard Deviation

The 95% confidence intervals for the standard deviation (SD) of 5 measurements is approximately 0.6*SD to 2.87*SD. The measurements are laser analyses to determine the atomic composition of a solid material. If each of the 5 measurements, stated above, actually consist of the average of 50...
12. ### Need help with this tricky average problem

The senior citizen rowing club team is made out of 10 members. In order to compete they need to have an average age of more than 55 years; the problem is that members do not want to reveal their age, neither to know the age of the others, nor the minimum or the maximum. They find a way to do it...
13. ### time series

Hi, just wondering whether someone can confirm how to do this properly, given a tabulated set of values of a time series for 4 quarters in each year 2004-2008, I've been asked to apply a centred 4 MA smoother to the time series and then construct the seasonally adjusted time series from this. I...
14. ### Anova test?

I have data for 09,10, and 2011. I have an exertion level for each individual. My indivduals are classified by the shift they work (8 day, 8 night, 12 day, 12 night). What is the test/method to use to tell if there is a difference between the 4 different shift vars in terms of exertion level...
15. ### satellite data precision

Hi all, I’m looking at some satellite data files. They are profiles of chemical atmospheric components and each profile has an associate estimate precision. I’d like to calculate some daily zonal average i.e. an average of many (about 400) profiles. The problem is that I’m not sure on the...