For the data set 6,5,10,11,13, the mean, x, is 9. what is the standard deviation?

3.39

Step-by-step explanation:     

We will use SD formula to find our answer.

= Standard deviation.

= Mean.

N= Numbers of data-points.

We have been given that mean of our data set is 9. So we will find the square of each data point's distance to the mean.

Now let us substitute our given values in above formula.

Upon adding the square of distances we will get,  

Upon dividing 46 by 4 we will get,

Upon taking square root of 11.5 we will get,

Therefore, the standard deviation for our given data set will be 3.39.  

arithmetic sequence

step-by-step explanation:

given that a sequence has terms as

19, 15, 11,

this is represented on a graph

the pattern indicates that the sequence is an arithmetic sequence with i term

a=19 and common difference d =-4

any general term

thus the sequence is reduced by 4 for each successive term starting from 1 and nth term is

24-5n.

first negative term would start after 5th term

5th term =24-25< 0

from 5th term onwards the sequence would be negative.