Which statement describes the solutions of this equation?

Lightbulbs of a certain type are advertised as having an average lifetime of 750 hours. The price of these bulbs is very favorab

Katyanochek1 [597]

Answer:

(a) Customer will not purchase the light bulbs at significance level of 0.05

(b) Customer will purchase the light bulbs at significance level of 0.01 .

Step-by-step explanation:

We are given that Light bulbs of a certain type are advertised as having an average lifetime of 750 hours. A random sample of 50 bulbs was selected, and the following information obtained:

Average lifetime = 738.44 hours and a standard deviation of lifetimes = 38.2 hours.

Let Null hypothesis, $H_0$ : $\mu$ = 750 {means that the true average lifetime is same as what is advertised}

Alternate Hypothesis, $H_1$ : $\mu$ < 750 {means that the true average lifetime is smaller than what is advertised}

Now, the test statistics is given by;

T.S. = $\frac{Xbar-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, X bar = sample mean = 738.44 hours

s = sample standard deviation = 38.2 hours

n = sample size = 50

So, test statistics = $\frac{738.44-750}{\frac{38.2}{\sqrt{50} } }$ ~ $t_4_9$

= -2.14

(a) Now, at 5% significance level, t table gives critical value of -1.6768 at 49 degree of freedom. Since our test statistics is less than the critical value of t, so which means our test statistics will lie in the rejection region and we have sufficient evidence to reject null hypothesis.

Therefore, we conclude that the true average lifetime is smaller than what is advertised and so consumer will not purchase the light bulbs.

(b) Now, at 1% significance level, t table gives critical value of -2.405 at 49 degree of freedom. Since our test statistics is higher than the critical value of t, so which means our test statistics will not lie in the rejection region and we have insufficient evidence to reject null hypothesis.

Therefore, we conclude that the true average lifetime is same as what it has been advertised and so consumer will purchase the light bulbs.

6 0

3 years ago

What could be the next statement that Ivan makes his proof?

natali 33 [55]

Answer: Choice A) Triangle ABC is similar to triangle ACD by AA

AA stands for Angle Angle. Specifically it means we need 2 pairs of congruent angles between the two triangles in order to prove the triangles similar. Your book might write "AA similarity" instead of simply "AA".

For triangles ABC and ACD, we have the first pair of angles being A = A (angle A shows up twice each in the first slot). The second pair of congruent angles would be the right angles for triangle ABC and ACD, which are angles C and D respectively.

We can't use AAS because we don't know any information about the sides of the triangle.

7 0

3 years ago

Nathan is going to invest in an account paying an interest rate of 4.9% compounded continuously. How much would Nathan need to i

Naily [24]

Answer:

731.48

Step-by-step explanation:

you take 6 percent form 100 percent with give 94 percent

then you times 1200 by 94 percent 8 times to get answer

6 1

3 years ago

Read 2 more answers

can someone please solve this? I clicked on homework help and it wasn't much help. I'm trying to turn in as much missing assignm

MA_775_DIABLO [31]

Answer:

One proportion to solve is 8/18 = x/8
Exact answer as a fraction: x = 32/9
Approximate answer in decimal form: x = 3.556

In reality, the 5's go on forever, but we have to round off somewhere.

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Explanation:

Break up the triangles as your teacher recommends. See the diagram below as to what I mean.

The smaller triangle has A = 8 as the horizontal side, and B = x as the vertical side

The larger triangle has C = 10+8 = 18 as the horizontal aside, and D = 8 as the vertical side.

We can form the proportion A/C = B/D.

A/C connects the horizontal sides (small/large) while B/D has the vertical sides tied together. The order of division is the same small over large. You could do large over small, but make sure you keep both sides consistent.

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Let's solve for x

A/C = B/D

8/18 = x/8

8*8 = 18*x .... cross multiply

64 = 18x

18x = 64

x = 64/18 .... divide both sides by 18

x = 32/9 exactly in fraction form

x = 3.556 approximately in decimal form

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Another proportion you can solve is A/B = C/D and you should get the same x value. It's the same as A/C = B/D because the B and C swap places. There are many other approaches you could take using different proportions.