Question

An outbreak of the deadly Ebola virus in 2002 and 2003 killed 91 of the 95 gorillas in 7 home ranges in the Congo. To study the spread of the virus, measure " distance" by the number of home ranges separating a group of gorillas from the first group infected. Here are data on distance and number of days until deaths began in each later group: Distance x x 1 5 4 6 3 5 Days y y 6 23 30 41 45 49 Use a calculator or software to find the following values. (a) Find the mean and standard deviation of x x . MEAN: equation editor Equation Editor STANDARD DEVIATION: equation editor Equation Editor (b) Find the mean and standard deviation of y y . MEAN: equation editor Equation Editor STANDARD DEVIATION: equation editor Equation Editor

Answer 1

a. Mean for x is

For standard deviation

Create the following table.

data	data-mean	(data - mean)2
1	-3	9
5	1	1
4	0	0
6	2	4
3	-1	1
5	1	1

Find the sum of numbers in the last column to get.

So

b. Similarly for y

Create the following table.

data	data-mean	(data - mean)2
6	-26.3333	693.44268889
23	-9.3333	87.11048889
30	-2.3333	5.44428889
41	8.6667	75.11168889
45	12.6667	160.44528889
49	16.6667	277.77888889

Find the sum of numbers in the last column to get.

Sample mean=