Download Obligatory assignment 1 : Descriptive statistics

Obligatory assignment 1 : Descriptive statistics
1. Open the dataset birth.sav. It can be downloaded from the course webpage:
www.uio.no/studier/emner/medisin/helseadm/HMM4101/h07/undervisningsplan.xml
Main menu: File -> Open-> Data ...
2. Data in SPSS can be viewed in Data view or Variable view. Data view shows all the
raw data. Variable view offers an overview of the variables: their description,
category, type, etc.
Which variables are categorical (qualitative) and which are numerical (quantitative).
Is age continuous or discrete in our sample?
3a. Make a frequency table and histograms for variables:
age of mother (age)
weight in pounds (wt)
Analyse-> Descriptive Statistics-> Frequencies. Click on ‘Statistics’ and mark
‘median’ and ‘mean’. Click on ‘Charts’ and mark ‘Histogram’ ‘with normal curve’.
Is there a relation between a frequency table and a histogram?
Are the distributions for ‘age’ and ‘wt’ normal?
What can we see from a relation between median and mean?
How large is the standard deviation? What does it say about the sample?
3b. A histogram can be made using several commands in SPSS.
Analyse-> Descriptive Statistics-> Explore. Now place ‘age’ on ‘Dependent List’.
Remove the cross from ‘Stem and leaf’.
What is a boxplot? Can we read from a boxplot if our sample is normally distributed?
4. Is the data representative for the whole population of Norwegian mothers?
What do we have to check?
5. Does smoking influence the birth weight of a baby?
Make a histogram and find median and mean for birth weight in grams (bwt) for the
two groups of mothers: group1 that smokes and group2 that does not smoke during the
pregnancy.
Make the histogram in the same way as described in 3b but put the smoking status
(smk) on the ‘Factor List’.
Are the distributions for the two groups normal?
6. Do mothers with hypertension have a tendency to have babies with a lower birth
weight?
Make a histogram and find median and mean for bwt just like in 5 but put history of
hypertension (ht) on the ‘Factor List’.
Why are the two histograms made in a different scale?
Can we conclude that hypertension has an effect on weight of a newborn? Why not?
7. Let’s look at the weight of expectant mothers. Repeat what you did in 5 but put race
(rac) on the ‘Factor List’.
Can we see any tendencies? Are expectant mothers of certain race heavier that the rest
of our sample?
Can we compare the three groups? Is there any problem?
8. General information about birth of babies can be found on Statistics Norway’s web
pages, www.ssb.no, under Population (‘befolkning’).
How many baby boys and baby girls were born in 2006?