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creativ13 [48]
3 years ago
12

Two distinct solid fuel propellants, type A and type B, are being considered for a space program activity. Burning rates of the

propellant are crucial. Random samples of 12 specimens of propellant A are taken with sample means of 84 cm/sec with a standard deviation of 4. And, random samples of 18 specimens of propellant B are taken with sample means of 77 cm/sec with a standard deviation of 6. Find a 99% confidence interval for the difference between the average burning rates for the two propellants. Assume the populations to be approximately normally distributed with equal variances.
Mathematics
1 answer:
Finger [1]3 years ago
6 0

Answer:

C.I. =  (2.297, 11.703)

Step-by-step explanation:

The t-statistic for difference of mean is given by,

t=\frac{\bar{x_{1}}-\bar{x_{2}}}{\sqrt{\frac{s_{1}^{2}}{n_{1}}+\frac{s_{2}^{2}}{n_{2}}}}

Here, \bar{x_{1}} = 84

\bar{x_{2}} = 7

s₁ = 4

n₁ = 12

s₂ = 6

n₂ = 18

Substituting all value in formula,

We get, t = -3.541 at 28 degree of freedom.

Using this formula, we get, t = 1.5342

Therefore, based on the data provided, the 99% confidence interval for the difference between the population means \bar{x_{1}}-\bar{x_{2}} is: 2.297 < \bar{x_{1}}-\bar{x_{2}} < 11.703

which indicates that we are 99% confident that the true difference between population means is contained by the interval (2.297, 11.703)

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Enter the numerator that makes the equation true.
Gelneren [198K]

Answer:

1 3/4

Step-by-step explanation:

First write the equation in mixed fraction form as;

1 3/4 + 1 1/3 = 1 _/12 + 1 4/12 ⇒  7/4  + 4/3 = _ + 16/12

7/4  + 4/3 = _ + 16/12

37/12 = _ + 16/12

37/12 - 16/12 = _

= 21/ 12

= 1 9/12

= 1 3/4

6 0
2 years ago
A projector displays an image on a wall. the area(in square feet) of the rectangular projection can be represented by
andrew-mc [135]

Answer:

The height of the projection will be (x - 5) feet.

Step-by-step explanation:

A projector displays an image on a wall. The area (in square feet) of the rectangular projection can be represented by (x² - 8x + 15).

Now to get the width and the height of the rectangular projection we have to factorize the expression (x² - 8x + 15).

Here, (x² - 8x + 15)

= x² - 3x - 5x + 15

= (x- 3)(x - 5)

Now, if the height of the projection is less than its width then, the height of the projection will be (x - 5) feet. (Answer)

3 0
3 years ago
The temperature today will be at least 10
kakasveta [241]

Answer:

10≤x

Step-by-step explanation:

x is the temputure

7 0
3 years ago
Follow the steps to finish solving the equation -3x+18=7x
Svet_ta [14]

Answer:

x = 1.8

Step-by-step explanation:

We have the equation -3x + 18 = 7x. First we do your step 1, and get: 18 = 10x. When doing your step 2, we divide both sides by 10 to isolate x alone. 18/10 = 1.8. X = 1.8

6 0
3 years ago
Explain how to find the estimated sum of 5/8+2/9 . Make sure to include at least one type of model.
OverLord2011 [107]
In this expression you would have to use the PEMDAS method. First divide, so (5 divided by 8) + (2 divided by 9). 
The answer you would get is: (0.625) + (0.222)
The final answer is: 0.847

8 0
3 years ago
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