Answer: 
Step-by-step explanation:
Given : Sample size : 
Sample mean : 
Standard deviation : 
Significance level : 
Critical value : 
Formula to find the confidence interval for population mean :-
Hence, a 90% confidence interval estimate of the population mean of all students =
Answer:
3-2x=15
Step-by-step explanation:
add 3 to both sides makes -2x=18. divide -2 from both side gets the answer x=-9, so the answer is C, -9
425 is decreased to 319.
The above statement means that a number should be deducted from 425 to get the difference of 319.
Let x be the unknown number.
425 - x = 319
425 - 319 = x
106 = x
106 is the unknown number.
It can be phrased like this: 425 decreased by 106 is 319.
Answer:
height of the Eiffel tower ≈ 300.0 m(nearest tenth of a meter)
Step-by-step explanation:
The triangle TDE is not a right angle triangle. Angle TDE can be gotten by subtracting 63° from 180°. Angle on a straight line is 180°. Therefore, 180° - 63° = 117
°.
angle TDE = 117°
angle DTE = 180° - 117° - 31° = 32°
DE = 346.4 m
Side TD can be find using sine law
346.4/sin 32° = TD/sin 31°
cross multiply
346.4 × 0.51503807491 = 0.52991926423TD
178.409189149 = 0.52991926423TD
divide both sides by 0.52991926423
TD = 178.409189149/0.52991926423
TD = 336.672397461
TD ≈ 336.67 m
The side TD becomes the hypotenuse of the new right angle triangle formed with the height of the Eiffel tower.
Using sin ratio
sin 63° = opposite/hypotenuse
sin 63° = h/336.67
cross multiply
h = 336.67 × 0.89100652418
h = 299.975166498
height of the Eiffel tower ≈ 300.0 m(nearest tenth of a meter)
Answer:
20,365.7 seconds
Step-by-step explanation:
First, we need to know how to convert yards to miles, as the question is in miles. We know that 1 mile is equivalent to 1760 yards. So we have:
1 mi = 1760 yards
If we multiply both sides by 81:
81 mi = 142,560 yards
And we know that the sprinter needs 8 second to run 56 yards:
8 s = 56 yards
If we divide both sides by 56 we get the time he needs for 1 yard:
8/56 s = 56/56 yards
1/7 s = 1 yard
So, takes him 1/7 seconds to run one yard. At this rate he runs 142,560 yards in:
(1/7) * 142,560 = 20,365.7
So, he needs 20,365.7 seconds to run 81 miles (142,560 yards)
