Answer:
-125
Step-by-step explanation:
Each term is 7 less than the previous term.
1st term: 15
2nd term: 15 - 7
3rd term: 15 - 7 - 7 = 15 - 2(7)
4th term = 15 - 7 - 7 - 7 = 15 - 3(7)
Notice that each term is 15 minus a multiple of 7. The multiple is obtained by multiplying 7 by 1 less than the term number.
The formula is:
For the 21st term, multiply 7 by 20, and subtract from 15.
7 × 20 = 140
15 - 140 = -125
Using the formula:
Answer: -125
1: It is a biography because it is describing/showing an event of a persons life through someone other than that person.
2: The text includes a <u>heading</u> and a <u>labeled diagram</u>
3: It allows you to better understand exactly when the events are taking place.
4: Because the text includes a labeled timeline that shows you the events in chronological order.
Hope I could help. ^^
Answer:
Step-by-step explanation:
Given
Required
Determine 
The question is illustrated with the attached image.
So:
This gives:
Standard deviation is calculated by
1. calculate mean, m
2. calculate deviation of EACH entry of data set from the mean, i.e.
d=(x-m)
3. calculate mean of square of deviations (d^2)/n to get variance,v
4. take square-root of variance to get standard deviation.
For example,
To find the standard deviation of data set {3,7,8}
1. mean=(3+7+8)/3=6
2. deviations, di={3-6,7-6,8-6}={-3,1,2}
3. squares of deviations, di^2={9,1,4}
4. mean of squares of deviations=(9+1+4)/3=14/3
Standard deviation=sqrt(14/3)=2.16
For the given data set, if you follow the above steps, you would get
sum=400
mean=400/9
variance (mean square of deviations)=8246/81
standard deviation=sqrt(8246/81)=sqrt(8246)/9
