Answer:
And replacing we got:
And the confidence interval for the difference of means would be given by:

Step-by-step explanation:
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
We have the following data given:

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 93% of confidence, our significance level would be given by
and
. And the critical value would be given by:
The confidence interval is given by:
And replacing we got:
And the confidence interval for the difference of means would be given by:

7.23 x 10^14
your want you answer in miles ... therefore you multiply 1.23 x 10^2 by 5.88 x 10^12
Step-by-step explanation:
if 39 passengers in 13 cars then 39 multiplied by 2 = 78 so 13 by 2 = 26 so the cars will be 26
Answer:
P(X<118.81)=0.0803
Step-by-step explanation:
Assuming the distribution for the mean life is approximately normal, with mean 120 months and variance 64 months^2, we can calculate the parameters for a sampling distribution with sample size = 89 computers.
The sampling distribution mean will be equal to the mean for a single computer:

The standard deviation will be adjusted by the sample size as:

With these parameters, we can calculate the z-score for X=118.81.

Then, the probability that the mean of a sample of 89 computers is less than 118.81 months is:

4r+14-r-6
Combine like terms
4r and -r are like terms and 14 and -6 are like terms.
(4r-r)+(14-6)
3r+8
Hope I helped!