Question

QUESTION 14 Problem 14) In order to make inference about average time SHSU students check their emails, a sample of 9 students was surveyed for how many times a day they check their emails. The responses were recorded as 20, 19, 15, 13, 27, 29, 19, 22, 25. (Question) Find the sample mean. QUESTION 15 Problem 15) In order to make inference about average time SHSU students check their emails, a sample of students was surveyed for how many times a day they check their emails. The responses were recorded as 20, 19.15, 13, 27, 29, 19. 22. 25. (Question) Find the sample standard deviation

Answer 1

Solution :

Here We have to find the sample mean and sample standard deviation

Formula of sample mean is:

$\bar{X} =\frac{ \sum{X_i}}{n}$

Where X_i is sample observations and "n" is sample size

Formula for sample standard deviation is:

$S = \sqrt{\frac{\sum{(X_i - \bar{X})^2}}{n-1}}$

From the above given sample data we have to find sample mean and sample standard deviation

a) sample mean :

$\bar{x}=\frac{(20+19+15+13+27+29+19+22+25)}{9} = 21$

Sample mean is : 21

b) Sample Standard Deviation :

$S = \sqrt{\frac{[(20-21)^2+(19-21)^2+(15-21)^2+........+(25-21)^2]}{9-1}} = \frac{226}{8}$

Sample standard deviation is 5.315 ~ 5.32