X in less than or equal to 4.5. it is this because 32 is the least number of miles per gallon. 144/32=4.5.
Formula for standard deviation sample calculation is:
SD = sqrt (( ∑( x - m)²) / ( n - 1 )),
where x stays for each value in the data set, m stays for mean of all values in the data set, and n stays for the number of values in the data set.
For example: Find the sample standard deviation for the set of numbers: 10, 11, 11, 12, 12.
First we will find mean of all avlues: m = ( 10 + 11 + 11 + 12 +12 ) / 5 = 11.2
SD = sqrt (( 1.2² + 0.2² + 0.2² + 0.8² + 0.8² ) / ( 5 - 1 ))=
= sqrt ( 2.8 / 4 ) = √0.7 = 0.837
When the last child has finished his or her schooling and is no longer dependent on the parents, the Echo stage begins. This is the pre-retirement or "empty nest" stage. For those individuals without children, the Echo stage begins about 10 years before retirement.
Answer:
yStep-by-step explanation:
Answer:
1. 9 or -9
2. 3.6 or -3.6
3. 12 and -12
4. The quadratic function has no real roots.
Step-by-step explanation:
1. Solve x² -81 = 0
x² -81 = 0
x² = 81
x = ±√81
x = 9 or x = -9
2. solve 2x² - 26 = 0
2x² - 26 = 0
2x² = 26
x² = 13
x = ±√13
∴ x = 3.6 or x = -3.6
3. f(x) = x² - 144
let f(x) = 0
x² - 144 = 0
x² = 144
x = ±√144
x = 12 and x = -12
4. f(x) = x² + 25
let f(x) = 0
x² + 25 = 0
x² = -25
x = ±√(-25)
There is no square root of a negative number. Its square is not a real number.
