Analysis of Dataset in Biostatistics

Biostatistics
Student Name:
Instructor Name:
Course Number:
16 April 2019

Assessment Task 1: Analysis of dataset
1. In your SPSS file, age (at time of enrolment) is given as a continuous variable.
a. What is the mean, standard deviation, minimum and maximum values for age?
Answer
The average age of the ACU cohort is 20.5 years old with a standard deviation of 4.89.
The minimum and maximum ages are 16 years old and 59 years old respectively.
Descriptive Statistics
N Minimum Maximum Mean Std. Deviation
AGE 38681 16 59 20.50 4.888
Valid N (listwise) 38681
b. What is the frequency (% and number) of students in each of these new age
categories?
Answer
Age group
Frequency Percent Valid Percent Cumulative
Percent
Valid
< 18 yrs. old 17760 45.9 45.9 45.9
19-21 yrs. old 11672 30.2 30.2 76.1
22-25 yrs. old 5494 14.2 14.2 90.3
> 26 yrs. old 3755 9.7 9.7 100.0
Total 38681 100.0 100.0
2. Descriptive statistics for the demographic information of the students
Answer
Demographic characteristics Frequency (n) Percent (%)
Cohort
2005 3259 8.4
2006 3615 9.3

2007 3944 10.2
2008 4086 10.6
2009 5010 13.0
2010 5687 14.7
2011 6383 16.5
2012 6697 17.3
Total 38681 100.0
State
NSW 15860 41.0
Victoria 13571 35.1
Queensland 7528 19.5
ACT 1722 4.5
Total 38681 100.0
Age
< 18 yrs. old 17760 45.9
19-21 yrs. old 11672 30.2
22-25 yrs. old 5494 14.2
> 26 yrs. old 3755 9.7
Total 38681 100.0
Living Arrangement
At home 20840 53.9
College/student
accommodation
6850 17.7
Independently 10991 28.4
Total 38681 100.0
Faculty
Arts and Sciences 9004 23.3
Education 15038 38.9
Health Sciences 11729 30.3
Theology and Philosophy 588 1.5
Business 2322 6.0
Total 38681 100.0
Degree Type
Single 34620 89.5
Double 4061 10.5
Total 38681 100.0
Metro
Metro 27223 70.4
Non-metro 5015 13.0

Missing 6443 16.7
Total 38681 100.0
Study Type
FT 34770 89.9
PT 3911 10.1
Total 38681 100.0
Fees Status
Domestic 32238 83.3
International 6443 16.7
Total 38681 100.0
The above table gives the frequencies for the demographic characteristics. As can be
seen, majority were the 2012 cohorts (17.3%, n = 6697) and most of the participants
came from NSW state (41.0%, n = 15860). In terms of age, majority were aged either 18
years old or less (45.9%, n = 17760). Most common living arrangement was living at
home (53.9%, n = 20840) and majority of the students were in the education faculty
(38.9%, n = 15038) with most students taking single degree programs (89.5%, n =
34620).
3. Testing for the difference in means
Answer
a. Gender
Difference in mean aggression scores
Group Statistics
GENDER N Mean Std. Deviation Std. Error Mean
driver_agg Male 10449 7.52 4.335 .042
Female 28232 7.51 4.347 .026
Independent Samples Test

Levene's Test for
Equality of
Variances
t-test for Equality of Means
F Sig. t df Sig. (2-
tailed)
Mean
Differen
ce
Std.
Error
Differen
ce
95% Confidence
Interval of the
Difference
Lower Upper
driver_agg
Equal variances
assumed
.117 .732 .083 38679 .934 .004 .050 -.093 .102
Equal variances
not assumed
.083 18712.8
03
.934 .004 .050 -.093 .102
An independent samples t-test was performed to compare the mean aggression scores for
the males and the female respondents. Results showed that the males (M = 7.52, SD =
4.34, N = 10449) had no significant difference in terms of the mean aggression scores
when compared to the females (M = 7.51, SD = 4.35, N = 28232), t (38679) = .083, p
> .05, two-tailed. The mean aggression scores for the males and the females are the same.
Difference in mean thrill seeking scores
Group Statistics
GENDER N Mean Std. Deviation Std. Error Mean
thrill Male 10449 5.00 1.217 .012
Female 28232 5.00 1.226 .007
Independent Samples Test
Levene's Test for
Equality of
Variances
t-test for Equality of Means

F Sig. t df Sig. (2-
tailed)
Mean
Differen
ce
Std.
Error
Differen
ce
95% Confidence
Interval of the
Difference
Lower Upper
thrill
Equal variances
assumed
.847 .357 -.370 38679 .711 -.005 .014 -.033 .022
Equal variances
not assumed
-.371 18783.2
50
.710 -.005 .014 -.033 .022
An independent samples t-test was performed to compare the mean thrill seeking scores
for the males and the female respondents. Results showed that the males (M = 5.00, SD =
1.22, N = 10449) had no significant difference in terms of the mean thrill seeking scores
when compared to the females (M = 5.00, SD = 1.23, N = 28232), t (38679) = .711, p
> .05, two-tailed. The mean thrill seeking scores for the males and the females are the
same.
Difference in mean risk acceptance scores
Group Statistics
GENDER N Mean Std. Deviation Std. Error Mean
risk_accep Male 10449 8.59 4.358 .043
Female 28232 8.51 4.357 .026
Independent Samples Test
Levene's Test for
Equality of
Variances
t-test for Equality of Means
F Sig. t df Sig. (2-
tailed)
Mean
Differen
ce
Std.
Error
Differen
ce
95% Confidence
Interval of the
Difference
Lower Upper