Answer: c. z = 1.35; Reject the null hypothesis
Step-by-step explanation:
Let 
be the average life expectancy of its batteries.
As per given , we have
Null hypothesis : 
Alternative hypothesis : 
Since 
is right-tailed and population standard deviation is also known, so we perform right-tailed z-test.
Test statistic : 
where, n= sample size
= sample mean
= Population mean
=population standard deviation
For 
, we have
Critical one-tailed test value for 0.10 significance level :
Decision : Since critical z value (1.28) < test statistic (1.35), so we reject the null hypothesis .
[When critical value is less than the test statistic value , we reject the null hypothesis .]
Answer:
5
Step-by-step explanation:
Answer:
x=1/2
Step-by-step explanation:
First you distribute the 8 over the (x-3) giving you 8x-24. Do the same for 2x and (4-17). That should give you 8x-34x.
Your equation should look like : 8x-24+7=8x-34x
Next try to balance out your equation. You want your x's all by themselves in order to solve.
The 8x's cancel eachother out so you have -24+7= -34x.
Add the like terms of -24 and 7 to get -17.
Equation: -17= -34x
Divide both sides by -34 to get x by itself.
-17/-34 = x
Reduce by dividing the numerator and denominator by 17 to get -1/-2
Since they are both negative the fraction turns positive.
So the answer should be x=1/2
I think that it is 270. 5400/180 = 30 8100/30 = 270
