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Answer:
Step-by-step explanation:
Hello!
a)
The given information is displayed in a frequency table, since the variable of interest "height of a student" is a continuous quantitative variable the possible values of height are arranged in class intervals.
To calculate the mean for data organized in this type of table you have to use the following formula:
X[bar]= (∑x'fi)/n
Where
x' represents the class mark of each class interval and is calculated as (Upper bond + Lower bond)/2
fi represents the observed frequency for each class
n is the total of observations, you can calculate it as ∑fi
<u>Class marks:</u>
x₁'= (120+124)/2= 122
x₂'= (124+128)/2= 126
x₃'= (128+132)/2= 130
x₄'= (132+136)/2= 134
x₅'= (136+140)/2= 138
Note: all class marks are always within the bonds of its class interval, and their difference is equal to the amplitude of the intervals.
n= 7 + 8 + 13 + 9 + 3= 40
X[bar]= (∑x'fi)/n= [(x₁'*f₁)+(x₂'*f₂)+(x₃'*f₃)+(x₄'*f₄)+(x₅'*f₅)]/n) = [(122*7)+(126*8)+(130*13)+(134*9)+(138*3)]/40= 129.3
The estimated average height is 129.3cm
b)
This average value is estimated because it wasn't calculated using the exact data measured from the 40 students.
The measurements are arranged in class intervals, so you know, for example, that 7 of the students measured sized between 120 and 124 cm (and so on with the rest of the intervals), but you do not know what values those measurements and thus estimated a mean value within the interval to calculate the mean of the sample.
I hope this helps!
Answer: 
Step-by-step explanation:
<h3>
The complete exercise is attached.</h3><h3>
</h3>
The area of a rectangle can be calculated with this formula:
Where "l" is the lenght and "w" is the width.
Then, you can notice that it can be obtained by multiplying the dimensions of the rectangle.
Knowing this, you can determine that the total area of the two flowers bed can be obtained by adding the products of their dimensions.
Since one of the rectangular flower bed is 2.78 feet by 4.81 feet and the other bed 2.78 feet by 5.61 feet, you can write the following expression to find the total area (in square feet)of the two beds:
If you factor out 2.78:
or 
Therefore, the expression that does not represent the total area in square feet of the two beds, is:
Answer:
x=5
y=7
Step-by-step explanation:
y = x+2 so plug that in the next equation as y
so it be --> 5x+(-4)(x+2)= -3 now use distributive property
(-4 times x)+(-4 times 2)= -4x+-8 replug that back in
5x-4x+-8 = -3 subtract your x
1x = x so ---> x+-8 = -3 now to get rid of -8 we have to add 8 to it
x= -3 but whatever you do to one side u do to the other so u have to add 8 to -3---> so it be x=5
now take that x=5 and plug it in to your first eqaiuton to get y
y=5+2 ---> y =7
Answer: $8.48
Step-by-step explanation: 8x.06 = .48 +8 = $8.48
