ERSH6300: SPSS Assignment 1 1
Dousay, Tonia February 8, 2010
Seeking to further investigate a link between malnutrition and retardation of brain
development, a child psychologist collected data from 32 babies (participants) during a span of
two weeks. Noting that babies with a low birth weight may be at risk for slower development,
data was reported according to gender and weight to the nearest ounce. Figure 1 illustrates this
breakdown.
Distribution of Gender
FIGURE 1. Distribution of gender (1=female, 2=male) on babies included in malnutrition study (N=32)
Source: Study 1 data collected over two weeks on 32 births.
Gender
ERSH6300: SPSS Assignment 1 2
Dousay, Tonia February 8, 2010
Figures 2 and 3 display the data as distributions of the variable weight for the entire
sample, regardless of gender. Figure 2 presents a stem and leaf plot of the data to show the
distribution to the nearest ounce, demonstrating a positively-skewed distribution.
Weight Stem and Leave Plot
Frequency Stem & Leaf
2.00 7 . 23 3.00 8 . 078 5.00 9 . 46689 6.00 10 . 455899 5.00 11 . 00223 3.00 12 . 114 3.00 13 . 049 2.00 14 . 44 2.00 15 . 00 1.00 16 . 1
Stem width: 10.00 Each leaf: 1 case(s)
FIGURE 2. Distribution of weight reported to the nearest ounce
Source: Study 1 data collected over two weeks on 32 births.
Figure 3 shows the distribution of birth weight around the median to the 1st and 3rd
quartiles with calculated outliers greater than 176.5 oz. and less than 48.5 oz. based upon
investigation using the Interquartile Range (IQR). According to the data, no outliers are present.
ERSH6300: SPSS Assignment 1 3
Dousay, Tonia February 8, 2010
FIGURE 3. Distribution of weight reported in Study 1 (to the nearest ounce)
Source: Study 1 data collected over two weeks on 32 births.
As indicated in Table 1, participant weight varied from a minimum of 72 ounces to a
maximum of 161 ounces with a mean of 112.44 ounces (SD=22.67 ounces). The median weight
for all participants reported was 109.5 ounces with a 1st quartile at 96.5 ounces and the 3rd
quartile at 128.5 ounces.
ERSH6300: SPSS Assignment 1 4
Dousay, Tonia February 8, 2010
TABLE 1. Descriptive statistics of the variable weight (oz.) for all participants (N=32).
Variable Mean SD Min Q1 Median Q3 Max
Weight 112.44 22.67 72 96.50 109.50 128.50 161
Source: Study 1 data collected over two weeks on 32 births.
Looking at each gender separately, Figure 4 presents a stem and leaf plot of the variable
weight for females (N=13). This distribution seems to approach a normal distribution.
Weight Stem and Leave Plot
Frequency Stem & Leaf
3.00 0 . 789 8.00 1 . 00011234 2.00 1 . 55
Stem width: 100.00 Each leaf: 1 case(s)
FIGURE 4. Distribution of weight reported to the nearest ounce of female participants (N=13)
Source: Study 1 data collected over two weeks on 13 births.
Table 3 summarizes data of the female weight group as mean, standard deviation, and 5-
point summary (minimum value – 1st quartile – median – 3rd quartile – maximum value). From
this, it is evident that the weights of female participants varied from a minimum of 73 ounces to
a maximum of 150 ounces with a mean of 115.77 ounces (SD=24.13 ounces). The median
ERSH6300: SPSS Assignment 1 5
Dousay, Tonia February 8, 2010
weight found for all female participants studied was 110 ounces with a first quartile of 100
ounces and third quartile of 141.50 ounces.
TABLE 2. Descriptive statistics of the variable weight (oz.) for female participants (N=13).
Variable Mean SD Min Q1 Median Q3 Max
Weight 115.77 24.13 73 100 110 141.50 150
Source: Study 1 data collected over two weeks on 13 births.
Looking at the male sample, Figure 5 presents a stem and leaf plot of the variable weight
for males (N=19). This distribution represents a positively-skewed distribution.
Weight Stem and Leave Plot
Frequency Stem & Leaf
1.00 7 . 2 2.00 8 . 07 4.00 9 . 4689 3.00 10 . 559 3.00 11 . 022 2.00 12 . 14 2.00 13 . 04 1.00 14 . 4 1.00 Extremes (>=161)
Stem width: 10.00 Each leaf: 1 case(s)
FIGURE 5. Distribution of weight reported to the nearest ounce of male participants (N=19)
Source: Study 1 data collected over two weeks on 19 births.
The mail weight group is summarized in Table 3 as mean, standard deviation, and 5-point
summary (minimum value – 1st quartile – median – 3rd quartile – maximum value). Weights of
male participants varied from a minimum of 72 ounces to a maximum of 161 ounces with a
ERSH6300: SPSS Assignment 1 6
Dousay, Tonia February 8, 2010
mean of 110.16 ounces (SD=21.98 ounces). The median weight found for all male participants
studied was 109 ounces with a first quartile of 96 ounces and third quartile of 124 ounces.
TABLE 3. Descriptive statistics of the variable weight (oz.) for male participants (N=93).
Variable Mean SD Min Q1 Median Q3 Max
Weight 110.16 21.98 72 96 109 124 161
Source: Study 1 data collected over two weeks on 19 births.
Table 2 shows that the 13 female participants exhibited a smallest weight of 73 ounces
with the largest at 150 ounces. Given that Table 3 shows that the smallest of the 19 male
participants weighed 72 ounces and the largest weighed 161 ounces, it is clear that male
participants experienced a greater range of birth weight. Furthermore, these numbers indicate
that the male participants included both the smallest and largest newborns. However, these same
figures show that female participants had a larger mean weight than the boys, at 115.77 ounces
and 110.16 ounces respectively. The females also had the larger standard deviation in weight at
24.13 ounces compared to the males at 21.98 ounces. As was indicated for the entire sample,
data for neither gender exhibited outliers.
With regard to concerns about low birth weight correlating to slow development, a factor
of two standard deviations below the mean was considered. In the case of Study 1, the standard
deviation for all births (N=32) was equal to 22.67 (mean=112.44). This places the high risk
factor at 67.10 ounces and below. Given that the minimum weight exhibited in the sample was
72 ounces, the study did not include a participant who was a high risk for slow development.
However, it should be noted that five of the participants in the study were born with birth
weights between one and two standard deviations below the mean, and could therefore be
ERSH6300: SPSS Assignment 1 7
Dousay, Tonia February 8, 2010
considered at risk for delayed development. Lastly, in terms of overall distribution of weight,
11.3% of the participants exhibited weight greater than 140 ounces and 83.9% of the participants
exhibited weight greater than 90 ounces.