run a simple linear regression to address your research question relating your two continuous variables together. Take the regression equation you obtain from SPSS and interpret the slope of the line. What are the assumptions? Please explain. What information does this give you that you weren’t able to obtain by running a simple correlation? Research Question 1: Is there a correlation between age
and total serum cholesterol levels?
Numerical Summary
The descriptive statistics reveal
that the sample consisted of 1000 individuals with a mean age of 50.88 years
(SD = 9.093) and a mean total serum cholesterol level (TOTCHOL) of 237.16 mg/dL
(SD = 43.370). As shown below, the age distribution appears slightly negatively
skewed (-1.161).
Descriptive Statistics
N
Minimum
Maximum
Mean
Std. Deviation
AGE
1000
33
69
50.88
9.093
TOTCHOL
990
129
464
237.16
43.370
Valid N (listwise)
990
The histogram below shows the distribution
of total serum cholesterol levels is slightly positively skewed (0.564).
Pearson Correlation
The correlation
analysis indicates a statistically significant positive correlation between age
and total serum cholesterol levels (r = 0.225, p < 0.01). Therefore, total
serum cholesterol levels tend to increase as age increases. The scatterplot.
Correlations
AGE
TOTCHOL
AGE
Pearson Correlation
1
.225**
Sig. (2-tailed)
.000
N
1000
990
TOTCHOL
Pearson Correlation
.225**
1
Sig. (2-tailed)
.000
N
990
990
**. Correlation is significant at the
0.01 level (2-tailed).
Research Question 2: Are smoking habits associated with
higher blood pressure?
Numerical Summary
Descriptives
HYPERTEN
Statistic
Std. Error
CIGPDAY
0
Mean
10.40
.761
95% Confidence Interval for Mean
Lower Bound
8.90
Upper Bound
11.90
5% Trimmed Mean
9.44
Median
5.00
Variance
137.274
Std. Deviation
11.716
Minimum
0
Maximum
40
Range
40
Interquartile Range
20
Skewness
.844
.158
Kurtosis
-.343
.315
1
Mean
8.73
.449
95% Confidence Interval for Mean
Lower Bound
7.84
Upper Bound
9.61
5% Trimmed Mean
7.31
Median
.00
Variance
152.807
Std. Deviation
12.362
Minimum
0
Maximum
60
Range
60
Interquartile Range
20
Skewness
1.388
.089
Kurtosis
1.381
.177
The bar
chart below indicates that most individuals in the sample had hypertension (758
cases) whereas only 237 cases had hypertension.
The mean number of cigarettes smoked per day is skewed as
shown below.
For those without hypertension (HYPERTEN = 0), the mean
number of cigarettes smoked per day was 10.40 (SD = 11.716). For those with hypertension (HYPERTEN = 1),
the mean number of cigarettes smoked per day was 8.73 (SD = 12.362).
