Answer:
[tex]\bar x =29.7[/tex]
[tex]\sigma = 6.81[/tex]
[tex]Median = 30.5[/tex]
Step-by-step explanation:
Given
[tex]Data:20,38,24,39,27,40,28,37,29,35,30,31,32,19,33,18,34,21,36,23[/tex]
[tex]n = 20[/tex]
Solving (a): The sample mean
This is calculated as:
[tex]\bar x =\frac{\sum x}{n}[/tex]
[tex]\bar x =\frac{20+38+24+39+27+40+28+37+29+35+30+31+32+19+33+18+34+21+36+23}{20}[/tex]
[tex]\bar x =\frac{594}{20}[/tex]
[tex]\bar x =29.7[/tex]
Solving (b): The standard deviation
This is calculated as;
[tex]\sigma = \sqrt{\frac{\sum(x-\bar x)^2}{n}}[/tex]
So, we have:
[tex]\sigma = \sqrt{\frac{928.2}{20}}[/tex]
[tex]\sigma = \sqrt{46.41}[/tex]
[tex]\sigma = 6.81[/tex]
Solving (c): The median
First, sort the data in ascending order
[tex]Sorted:18,19,20,21,23,24,27,28,29,30,31,32,33,34,35,36,37,38,39,40[/tex]
The position of the median is calculated as:
[tex]Median = \frac{n+1}{2}[/tex]
[tex]Median = \frac{20+1}{2}[/tex]
[tex]Median = \frac{21}{2}[/tex]
[tex]Median = 10.5th[/tex]
The 10.5th item represents the mean of the 10th and 11th item.
So, median is:
[tex]Median = \frac{30+31}{2}[/tex]
[tex]Median = \frac{61}{2}[/tex]
[tex]Median = 30.5[/tex]
