# Recent content by Clarkson

1. ### Issue in Interpreting SPSS output of GLM repeated measures

I have a data set with repeated measures for each individual. That is there a re two groups, treatment and control. And each individual is measured at 3 time points. But there are missing values. That is I don't have data for all 3 time points for all of the individuals. I carried out a SPSS GLM...
2. ### ARMA one step ahead forecast and forecast error

For a ARMA(1,1) process with constant \theta is X_t=\alpha X_{t-1}+\theta +Z_t+\beta Z_{t-1} where Z_T is white noise with mean 0 and variance\sigma ^2. 1)Find the one step ahead forecast 2)Find the expected value and variance of one step ahead forecast error Here's what I did...
3. ### Changing a target value that minimize the product being outside the specifications in

I was doing problems in the article here. http://elearning.vtu.ac.in/10/enotes/06IPIM65/Mod10-NVN.pdf In the question on page 16 I don't understand part b) how to find a target value that minimize the product being outside the specifications. Can someone please explain to...
4. ### Changing process average in control charts

Data is given for a X bar and R chart of subgroup size=4. . The control limits are for X bar chart: center line=178.46 UCL=184.1146 LCL=172.8054 for R chart: center line=8.3888 UCL=17.734 LCL=0 In this question I don't understand to do the following part : . Can...
5. ### Finding a UMVUE for variance of normal distribution

Let Let X_1,X_2,...,X_n be a random sample from a normal distribution with mean \mu and variance \sigma^2 . I showed that (\bar X,S^2) is jointly sufficient for estimating ( \mu , \sigma^2 ) where \bar X is the sample mean and S^2 is the sample variance. Then assuming that (\bar...
6. ### Dgrees of freedom of error sum of squares

For a given metal a experiment was carried out to measure the heat variation with temperature in Celsius.The heat was measured twice at each chosen temperature. If the chosen temperatures are 30,40,75,85,90 Then there would be total of 10 observations(2 for each temperature).In order...
7. ### categorical variables in regression analysis and interaction terms

I am learning multiple regression with categorical variables and in a book I came across this problem. For yield of corn suppose there are two factors affecting, nitrogen level and depth of ploughing. Say there are three nitrogen categories(1,2,3) and two depth categories(1,2). There's...
8. ### Interaction terms in regression-theory

I am learning categorical variables and interaction terms in the regression course and there few things I don't understand. Suppose a salary data set with predictors experience X in years Education coded 1 for diploma , 2 for degree, 3 for higher degree Management M coded as 1 for a...
9. ### validity of regression assumptions on residual plot

I am learning regression course.For a homework given the residual plot I have to analyze it.This is how I interpreted it.I want to know if there are any wrong interpretations. 1)Since the variability at each x is not the same,there is non constant variance. 2)The residuals are not randomly...
10. ### proof of E(EMS)=sigma^2

How can I prove expected value of error mean square E(EMS)=\sigma^2. I showed that ESS=S_{YY}-\hat\beta_1^2 S_{XX} Thus E(EMS)= E[{S_{YY}-\hat\beta_1^2 S_{XX}\over n-2}] I am stuck in computing E[S_{YY}].
11. ### Using estimators for goodness of fit test

This is a practice question I came across when dong some goodness of fit test examples.A company sells cloths by mail order.The size of clothes is defined by hip size; thus the height of customers of a particular customer may vary considerably. Data set of heights sent in by customers of size...
12. ### Obtaining sample variance from grouped data for goodness of fit test

This is a practice question I came across when dong some goodness of fit test examples.A company sells cloths by mail order.The size of clothes is defined by hip size; thus the height of customers of a particular customer may vary considerably. Data set of heights sent in by customers of size 18...
13. ### Goodness of fit test for a normal ditribution

In the example from a site I was trying out http://www.cimt.plymouth.ac.uk/projects/mepres/alevel/fstats_ch5.pdf this problem in page 107 about Goodness of fit test for a normal distribution.Question is about analysis of fat content of hambergers. I understand that we need to have the two...
14. ### Goodness of fit test for exponential distribution

The given data below shows the time in intervals in seconds between successive white cars in flowing traffic in an open road.Can these be modeled by an exponential distribution. I am computing the expected frequencies by calculating the probability at each interval.Under null hypothesis as...
15. ### Writing null hypothesis and deciding on rejection criteria

The number of faults in one metre of a thread is Poisson distributed.It is claimed that the average number of faults is 0.02 per metre.A random sample of 100 one metre lengths of the thread reveals a total of 6 faults.Does this information support the claim? What I want to know whether my H0...