In: Statistics and Probability
52 randomly selected students were asked how many siblings were
in their family. Let X represent the number of pairs of siblings in
the student's family. The results are as follows:
| # of Siblings | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 
|---|---|---|---|---|---|---|---|
| Frequency | 10 | 11 | 7 | 4 | 5 | 10 | 5 | 
Round all your answers to 4 decimal places where
possible.
The mean is:
The median is:
The sample standard deviation is:
The first quartile is:
The third quartile is:
What percent of the respondents have at least 4 siblings? %
72% of all respondents have fewer than how many siblings?
Answer:
Given Data,
52 randomly selected students were asked how many siblings were in
their family.
Let X represent the number of pairs of siblings in the student's
family.
The results are as follows:
| # of Siblings(x) | Frequency(f) | f x | 
(f x)2 | 
| 0 | 10 | 0 | 0 | 
| 1 | 11 | 11 | 121 | 
| 2 | 7 | 14 | 196 | 
| 4 | 5 | 20 | 400 | 
| 5 | 10 | 50 | 2500 | 
| 6 | 5 | 30 | 900 | 
 f=48 | 
 f x=125 | 
 (f x)2=4117 | 
(a). To find Mean:

Therefore, mean is 2.6042
(b). To find Median:
Median= (Value of 
 observation+Value of 
observation)/2
Median=(Value of 
observation+Value of 
observation)/2
Median=(Value of 24th observation+Value of 25th observation)/2
Median=(2+2)/2
Median=4/2
Therefore, Median=2
(c).To find sample standard deviation:
Sample Standard Deviation   





Therefore, Sample Standard Deviation S=8.9816
(d).First Quartile:
Q1= 
   value of the observation
Q1= 
   value of the observation
Q1= 
   value of the observation
Q1= 
   value of the observation
Q1=1
Therefore Q1=1.
(e).Third Quartile:




Q3=37th value of observation
Q3=4
Therefore Q3=4
(f).
The percent of the respondents have at least 4 siblings=

%
Therefore, the percent of the respondents have at least 4
siblings=41.67%.
(g).
72% of all respondents have fewer than how many siblings,
i.e,72% of 48 is=34.56=35
35th Value of observation is 5
Therefore, 72% of all respondents have fewer than the 5 siblings.