A distance AB is observed repeatedly using the same equipment and procedures, and the results, in meters, are listed below:69.401, 69.400, 69.402, 69.396, 69.406, 69.401, 69.396, 69.401, 69.405, and 69.404Calculate (a) the line's most probable length, (b) the standard deviation.

The line's most probable length is 69.4012 meters.

The standard deviation is 0.0032 meters.

Step-by-step explanation:

We are given the following in the question:

69.401, 69.400, 69.402, 69.396, 69.406, 69.401, 69.396, 69.401, 69.405, 69.404      

Formula:

where are data points, is the mean and n is the number of observations.  

The line's most probable length is 69.4012 meters.

Sum of squares of differences = 0.0001016

The standard deviation is 0.0032 meters.

he used the algebra tiles correctly.

step-by-step explanation:

given : 3x(2x-1)

solution :

since he used algebra tiles .

armando's solution is the same in the solution shown in figure

as he distributed 2x into x and x and wrote them vertically

and also write   -1 vertically

and 3x into x and x and x and wrote it horizontally

performing the multiplication in the algebra tiles we get

and solving the given expression :

3x(2x-1)

since solving the expression using tiles   and solving the expression algebraically we get the same answer

thus   we can choose the first statement as the answer to this problem which is "he used the algebra tiles correctly".