Answer:
The 90% confidence interval for the mean usage of electricity is between 17.4 kwH and 17.6 kwH
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
So it is z with a pvalue of 1-0.05 = 0.95, so z = 1.645
Now, find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
So
The lower end of the interval is the mean subtracted by M. So 17.5 - 0.14 = 17.4 kwH
The upper end of the interval is M added to the mean. So 17.5 + 0.14 = 17.6 kwH
The 90% confidence interval for the mean usage of electricity is between 17.4 kwH and 17.6 kwH
Answer: 75-watt are 30$ fluorescent are 30$ in the second and 65$ in the first
Step-by-step explanation: i calculated thirty 75-watt and the fluorescent and got these kinda hard to explain hope i helped:)
<h2>
Hello!</h2>
The answer is:
The correct option is the third option;
<h2>
Why?</h2>
To find which of the options expresses the intersection of the three days as an inequality in terms of temperature "t" we need to find an inequality which starts at the lowest temperature (greater or equal) and finish at the highest temperature (less or equal).
So, we have that the lowest temperature is -23°F and the highest temperature is 50°F, there are two options for that range, but we need to consider that the temperature will range from -23° to 50°, so, the correct option is the third option;
We can see that the inequality express that the temperature will range from -23°F being greater or equal than that, to 50°F being less or equal than that.
Have a nice day!
P(centre engine and left fail) = 0.004 x 0.007 = 0.000028
P(centre engine and right fail) = 0.004 x 0.007 = 0.000028
P(all three engines fail) = 0.004 x 0.007 x 0.007 = 0.000000196
P(plane will crash) = 0.000028 x 2 + 0.000000196 = 0.000056196
