Answer: The standard deviation was calculated incorrectly.
Step-by-step explanation:
- The standard deviation measures the dispersion of the data values from the mean value.
It cannot be negative , because it is the square root of the variance .
We add all squared deviations from the data points away from the mean and (then divide it by the number of data values) to evaluate variance.
Since , any squared number cannot give a negative result.
⇒ Standard deviation cannot be negative.
⇒The standard deviation was calculated incorrectly.
Rest other things (given in options) can not be interpreted on the basis of given information.
Answer:
C
Step-by-step explanation:
14. 1.5, 10 <- Answer
15. 5,1 <- Answer
Proof 14
Solve the following system:
{2 x - y = -7 | (equation 1)
4 x - y = -4 | (equation 2)
Swap equation 1 with equation 2:
{4 x - y = -4 | (equation 1)
2 x - y = -7 | (equation 2)
Subtract 1/2 × (equation 1) from equation 2:
{4 x - y = -4 | (equation 1)
0 x - y/2 = -5 | (equation 2)
Multiply equation 2 by -2:
{4 x - y = -4 | (equation 1)
0 x+y = 10 | (equation 2)
Add equation 2 to equation 1:
{4 x+0 y = 6 | (equation 1)
0 x+y = 10 | (equation 2)
Divide equation 1 by 4:
{x+0 y = 3/2 | (equation 1)
0 x+y = 10 | (equation 2)
Collect results:
Answer: {x = 1.5
y = 10
Proof 15.
Solve the following system:
{5 x + 7 y = 32 | (equation 1)
8 x + 6 y = 46 | (equation 2)
Swap equation 1 with equation 2:
{8 x + 6 y = 46 | (equation 1)
5 x + 7 y = 32 | (equation 2)
Subtract 5/8 × (equation 1) from equation 2:{8 x + 6 y = 46 | (equation 1)
0 x+(13 y)/4 = 13/4 | (equation 2)
Divide equation 1 by 2:
{4 x + 3 y = 23 | (equation 1)
0 x+(13 y)/4 = 13/4 | (equation 2)
Multiply equation 2 by 4/13:
{4 x + 3 y = 23 | (equation 1)
0 x+y = 1 | (equation 2)
Subtract 3 × (equation 2) from equation 1:
{4 x+0 y = 20 | (equation 1)
0 x+y = 1 | (equation 2)
Divide equation 1 by 4:
{x+0 y = 5 | (equation 1)
0 x+y = 1 | (equation 2)
Collect results:
Answer: {x = 5 y = 1
Answer:
125.6 cm²
Step-by-step explanation:
Area of the shaded region = area of larger circle - area of the smaller circle
Area of the smaller circle = πr²
π = 3.14, r = 3 cm
Area of smaller circle = 3.14*3² = 3.14*9 = 28.26 cm²
Area of larger circle = πr²
π = 3.14, r = 7
Area of larger circle = 3.14*7² = 3.14*49 = 153.86 cm²
Area of the shaded region = 153.86 - 28.26 = 125.6 cm²
