The measures of spread include the range, quartiles and the interquartile range, variance and standard deviation. Let's consider each one by one.
<u>Interquartile Range: </u>
Given the Data -> First Quartile = 2, Third Quartile = 5
Interquartile Range = 5 - 2 = 3
<u>Range:</u> 8 - 1 = 7
<u>Variance: </u>
We start by determining the mean,

n = number of numbers in the set
Solving for the sum of squares is a long process, so I will skip over that portion and go right into solving for the variance.

5.3
<u>Standard Deviation</u>
We take the square root of the variance,

2.3
If you are not familiar with variance and standard deviation, just leave it.
Negative, You'll have to explain the why part though,
Answer:
an = -4 * (-3)^ (n-1)
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Step-by-step explanation:
We can find the common ratio
12/-4 = -3
r =-3
The explicit formula is
an =a1 r^(n-1)
an = -4 * (-3)^ (n-1)
We want the 18 th term
a 18 = -4 (-3) ^ 17
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Answer:
19
Step-by-step explanation:
9+10 is 19.