60 randomly selected students were asked how many siblings were in their family. Let X = the number of pairs of siblings in the student's family. The results are as follows: Siblings Frequency 1 13 2 22 3 15 4 6 5 3 6 0 7 1 Round your answers to two decimal places. 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 had less than 3 siblings? % 20% of all respondents have had at most how many siblings?

Respuesta :

Answer:

i) mean =  2.466667   = 3 (approx.)

ii) median = 2

iii) standard deviation = 1.241468

iv) 1st quartile (Q1) = 2

v) 3rd quartile (Q3) = 3

vi) Percentage of respondent having <3 siblings = (35/60)*100 = 58.3%

vii) 20% of all respondents have had at most how many siblings = 1 sibling

Step-by-step explanation:

The first step is to form a frequency distribution from the information given. This is as follows:

Number of siblings | Frequency

1                                | 13

2                               | 22

3                               | 15

4                               | 6

5                               | 3

6                               | 0

7                               | 1

Having done this, we can compute the mean, median and standard deviation.

i) Mean ([tex]\bar{x}[/tex]) = [tex]\frac{\sum{fx}}{\sum{f}}[/tex],

Where f - frequency and x - is the number of siblings. Thus, fx is a f multiply by x.

ii) We do the same for median = L + {n/2 - Cf}c

That is, L - is the lower class boundary of the median class, n is the sample size, Cf is the cumulative frequency before the median class and c is the class size.

iii) Standard deviation = [tex]\sqrt{variance} = \sqrt{\frac{\sum{(f(x - \bar{x}))^2}}{\sum{f-1}} }[/tex],

iv) 1st quartile = L1 + {(n/4) - Cf}c

v) 3rd quartile = L3 + {(3n/4) - Cf}c

vi) Percentage of respondent having <3 siblings = number of those having <3 siblings/ n = 60 = (13+22)/60 = 35/60.

vii) 20% of all respondents have had at most how many siblings = 1 sibling.