Answer:
(1) N or n = 20
(2) [tex]\bar X \text{ or } \mu[/tex] = 43.4
(3) σ = 9.78 and s = 10.04.
Step-by-step explanation:
We are given with the following data set below;
{51, 48, 42, 43, 48, 48, 46, 15, 29, 45, 47, 55, 46, 35, 47, 48, 54, 26, 53, 42}
(1) As we can see in the above data that there are 20 data values in our data set which means that the value of N or n (numner of observations) is 20.
(2) The formula for calculating Mean of the data, i.e. [tex]\bar X \text{ or } \mu[/tex] is given by;
Mean = [tex]\frac{\sum X}{n}[/tex]
= [tex]\frac{51 +48+ 42+ 43+48+48+ 46+ 15+ 29+ 45+ 47+ 55+ 46+ 35+ 47+ 48+ 54+ 26+ 53+ 42}{20}[/tex]
= [tex]\frac{868}{20}[/tex] = 43.4
So, the value of [tex]\bar X \text{ or } \mu[/tex] is 43.4.
(3) The formula for calculating population standard deviation ([tex]\sigma[/tex]) is given by;
Standard deviation, [tex]\sigma[/tex] = [tex]\sqrt{\frac{\sum (X - \bar X)^{2} }{N} }[/tex]
= [tex]\sqrt{\frac{(51-43.4)^{2}+(48-43.4)^{2}+.......+(42-43.4)^{2} }{20} }[/tex]
= 9.78
Similarly, the formula for calculating sample standard deviation (s) is given by;
Sample Standard deviation, s = [tex]\sqrt{\frac{\sum (X - \bar X)^{2} }{n-1} }[/tex]
= [tex]\sqrt{\frac{(51-43.4)^{2}+(48-43.4)^{2}+.......+(42-43.4)^{2} }{20-1} }[/tex]
= 10.04
