We will have to use the formula for the area of a trapezoid on this problem, which is ( and
are the bases of the trapezoid and
is the height):
All we need to do is substitute the information we are given into our formula:
Now, let's just simplify the equation:
The missing base has a length of 13 units.
Option c is the correct answer which represents the numerator in the calculation of variance and standard deviation.
<h3>What are the variance and standard deviation? </h3>In statistics, variance is a measure of the variation of data from the mean, whereas standard deviation is the measure of the normal distribution of statistical data.
A contractor records the areas, in square feet, of a small sample of houses in a neighborhood to determine data about the neighborhood.
2,400; 1,750; 1,900; 2,500; 2,250; 2,100
we need to find which of the following represents the numerator in the calculation of variance and standard deviation.
(225 + (–425
+ (–275
+ (325
+ (75
+ (–75
= 423,750
(650 + (–150
+ (–600
+ (250
+ (150
+ (–300
= 980,000
(250 + (–400
+ (–250
+ (350
+ (100
+ (–50
= 420,000
92416.60
The variance is 84000
The standard deviation is 290
mean = (2400+1750+1900+2500+2250+2100)/6
mean = 2150
Subtract the data values from the mean to get
2400-2150 = 250
1750-2150 = -400
1900-2150 = -250
2500-2150 = 350
2250-2150 = 100
2100-2150 = -50
The differences are 250, -400, -250, 350, 100, -50
Then you square those values and add up the squares
(250)^2 + (-400)^2 + (-250)^2 + (350)^2 + (100)^2 + (-50)^2 = 420,000
Hence, option c is the correct answer which represents the numerator in the calculation of variance and standard deviation.
Learn more about variance;