The formula for standard deviation of a sample is: s equals square root of fraction numerator 1 over denominator n minus 1 end fraction sum from i equals 1 to n of open parentheses X subscript i minus X with bar on top close parentheses squared end root

Select the true statement for the following data set that has a mean of 5:

2, 4, 4, 4, 5, 5, 5, 7, 9

i think the amount would be $140.62

this is a direct variation proportion. y = kx

y is the total amount due, k is the constant of variation, and x is the number of texts sent.

plug in the 3.20 and the 16 to solve for the "k". this is the constant of proportionality. it is the value that will not change.

3.20 = k(16). solving you get $.20 per text.

the equation would then be y = .20x

perimeter = 10 +  √10  units

explanation:

first, we will need to get the length of each line using the distance formula which is as follows:

distance = 

1- length of ab:

ab =   = 5 units

2- length of ac

length of ac is the same as ab = 5 units

3- length of bc:

bc =   =  √10  units

now, we can get the perimeter by adding the side lengths as follows:

perimeter = 5 + 5 +  √10

perimeter = 10 +  √10  units

hope this : )

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