Suppose a regional computer center wants to evaluate the performance of its memory system. One measure of performance is the average time between failures of its disk drive. To estimate the value, the center recorded the time between failures for a random sample of 45 drive failures. The sample mean has been computed to be 1,762 hours and the sample standard deviation is 215. Estimate the true mean time between failures with a 90% confidence interval? Interpret the confidence interval.
Answers
Answer:
The 90% confidence interval is (1408.325 hours, 2115.675 hours).
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 , so
Now, find M as such
In which s is the standard deviation of the sample. So
The lower end of the interval is the mean subtracted by M. So it is 1762 - 353.675 = 1408.325 hours.
The upper end of the interval is the mean added to M. So it is 6.4 + 0.3944 = 2115.675 hours.
The 90% confidence interval is (1408.325 hours, 2115.675 hours).
Related Questions
Please help me thank you so much. Just not sure of my answers
The director of student health at a large university was concerned that students at his school were consuming too many calories each day. For a certain population of college-age students, it is recommended to consume around 2,000 calories/day. The director would like to test the hypothesis that H0:μ=2000 vs. HA:μ>2000. In a random sample of 50 students the director found that the average was 2105 calories/day with a standard deviation of 288 calories/day. Calculate the appropriate test statistic for this situation. Round your answer to 3 decimal places.
What is the quotient and remainder of 8 divided 25
I need help ASAP !!!
B. 80
C. 86
D. 16
Answers
Explanation: I started with 30 then reversed everything so I subtracted 10, multiplied by 4, and then added 6, and got the number 86. Then I checked the answer by subtracting 6 from 86, then divided it by 4, added it to 10, and the final number equaled 30.
I hope this is the answer you were looking for! I’m so sorry if it’s wrong!
sin 2x sin x + cos x= 0
Answers
Use the double angle identity:
sin(2x) = 2 sin(x) cos(x)
Now rewrite
sin(2x) sin(x) + cos(x) = 0
as
2 sin²(x) cos(x) + cos(x) = 0
Factor out cos(x) :
cos(x) (2 sin²(x) + 1) = 0
Consider the two cases,
cos(x) = 0 OR 2 sin²(x) + 1 = 0
Solve for cos(x) and sin²(x) :
cos(x) = 0 OR sin²(x) = -1/2
Squaring a real number always gives a non-negative number, so the second case doesn't offer any real solutions. We're left with
cos(x) = 0
Cosine is zero for odd multiples of π/2, so we have
x = (2n + 1) π/2
where n is any integer.
Answers
Answer: height of kite is 147.042 feets
Step-by-step explanation:
The diagram of the kite is shown in the attached photo
Triangle ABC is formed and it is a right angle triangle.
The kite string made an angle of 33 degrees with the ground. The string used was 90 yards We will convert the 90 yards to feets.
I yard = 3 feets
90 yards would become
90×3 = 270 feets
This 270 feets form the hypotenuse of the triangle.
To determine the height of the kite h, we will use trigonometric ratio
Sin# = opposite / hypotenuse
Where
# = 33 degrees
Hypotenuse = 270 feets
Opposite = h feets
Sin 33 = h/270
h = 270sin33
h = 270 × 0.5446 = 147.042 feets
Answers
Answer:
The key features are
50ft³ = the volume
0.5ft³/min = rate
Time= 100 minutes
Step-by-step explanation:
Chiang is filling a 50ft container with water at a rate of 0.5 ft/ min.
50ft³ = the volume
0.5ft³/min = rate
There is a key future missing which is the time it will take to fill the 50 ft³ container
Time = volume/rate
Time= 50 ft³/0.5ft³/min
Time= 50/0.5 min
Time = 100 min
The key features are
50ft³ = the volume
0.5ft³/min = rate
Time= 100 minutes
Answers
x=
Answers
Answer:
x = 80
Step-by-step explanation:
9+1=10 so x/8 must equal 10.
80/8 = 10 and subract by 9 = 1
2. -1• X/-1 = 1• -1
( multiple -1 by both sides)
3. X= -1
I hope this helps