Answer:
a) There is no enough evidence of an increase in life expectancy.
b) P-value=0.07.
The P-value indicates that this sample result is not rare to happen (is greater than the significance level) even if the mean of the population is still 87 hours.
Step-by-step explanation:
We have to perform a hypothesis test on the mean, with known standard deviation of the population.
The null hypothesis, which we will reject or not, states that the life expectancy has not increase (it stays equal or less than 87 hours).
The null and alternative hypothesis are
The significance level is α=0.01.
The z-value is
The P-value for z is
The P-value (0.07) is greater than the significance level (0.01), so the effect is not significant. We fail to reject the null hypothesis.
There is no enough evidence of an increase in life expectancy.
Both <em>Px</em> + <em>Qy</em> = <em>R</em> and <em>Tx</em> + <em>Uy</em> = <em>V</em> have the same solution (2, 9), meaning the point (2, 9) lies on both lines such that <em>x</em> = 2 and <em>y</em> = 9 makes both equations true.
When you add these equations together, you get
(<em>Px</em> + <em>Qy</em>) + (<em>Tx</em> + <em>Uy</em>) = <em>R</em> + <em>V</em>
→ (<em>P</em> + <em>T</em> ) <em>x</em> + (<em>Q</em> + <em>U</em> ) <em>y</em> = <em>R</em> + <em>V</em>
so the first option is equivalent.
When you subtract the first equation from the second, you get
(<em>Tx</em> + <em>Uy</em>) - (<em>Px</em> + <em>Qy</em>) = <em>V</em> - <em>R</em>
→ (<em>T</em> - <em>P</em>) <em>x</em> + (<em>U</em> - <em>Q</em>) <em>y</em> = <em>V</em> - <em>R</em>
so the third option is also equivalent.
Answer:
3/5y
Step-by-step explanation:
6y/35 ÷10y^2/7
to solve this you do reciprocal of 10y^2/7
then;
6y/35 x 7/10y^2
solving this
3/5y
A+b=13
a-b=7
add the two equations using system of equations
2a=20
a=10
10+b=13
b=3