Practical 5
Conducting a Survey
This practical will demonstrate how serious the consequences can be if you skip screening steps
before doing analyses. If you have any questions about how to perform the
analyses/techniques of today's practical in SPSS, your standard SPSS book will be a sufficient
reference. For most students this has been the book by Andy Field: Discovering Statistics Using
SPSS.
In this practical there are a couple of questions to which the answers can be graded. These
questions are denoted by [HAND IN]. Hand it in no later than Monday December 16, 9AM,
by sending it to . Name the file P#-yourlastname(s).pdf, for example: P1-
Struminskaya_Elevelt.pdf.
Your attendence at the practicals is required. However, if you are finished, you may leave.
All the best,
Anne and Bella
1. Open the file Simulated assumptions.sav. As the name of the file states this is
simulated data, created to show you the importance of screening and checking model
assumptions. In reality, violations are hardly this severe (or obvious), but (milder)
violations do occur regularly. Always screen your data and check the most important
model assumptions!
In (a) ignore any screening. In step (b) and (c) you do check for mistakes and outliers and in the
end you can see how serious the consequences can be if you skip this screening step before
doing analyses [compare results of (a), (b) and (c)].
(a) [HAND IN] Run a regression analysis with y as dependent variable and x1, x2 and x3 as
predictors. Report: R2 (plus its significance value), as well as the β-values (with
significances) of each of the three predictors. Also report the Valid N (sample size used
for the analysis).
– R2: .005 p-value: .738
– β x 1: .000, p-value: .998
– β x 2: -.062, p-value: .364
– β x 3: -.011 p-value: .875
– Valid N: 281
Conducting a Survey
This practical will demonstrate how serious the consequences can be if you skip screening steps
before doing analyses. If you have any questions about how to perform the
analyses/techniques of today's practical in SPSS, your standard SPSS book will be a sufficient
reference. For most students this has been the book by Andy Field: Discovering Statistics Using
SPSS.
In this practical there are a couple of questions to which the answers can be graded. These
questions are denoted by [HAND IN]. Hand it in no later than Monday December 16, 9AM,
by sending it to . Name the file P#-yourlastname(s).pdf, for example: P1-
Struminskaya_Elevelt.pdf.
Your attendence at the practicals is required. However, if you are finished, you may leave.
All the best,
Anne and Bella
1. Open the file Simulated assumptions.sav. As the name of the file states this is
simulated data, created to show you the importance of screening and checking model
assumptions. In reality, violations are hardly this severe (or obvious), but (milder)
violations do occur regularly. Always screen your data and check the most important
model assumptions!
In (a) ignore any screening. In step (b) and (c) you do check for mistakes and outliers and in the
end you can see how serious the consequences can be if you skip this screening step before
doing analyses [compare results of (a), (b) and (c)].
(a) [HAND IN] Run a regression analysis with y as dependent variable and x1, x2 and x3 as
predictors. Report: R2 (plus its significance value), as well as the β-values (with
significances) of each of the three predictors. Also report the Valid N (sample size used
for the analysis).
– R2: .005 p-value: .738
– β x 1: .000, p-value: .998
– β x 2: -.062, p-value: .364
– β x 3: -.011 p-value: .875
– Valid N: 281
