Find the missing value to the nearest hundredth. cos (_____

A manufacturer produces light bulbs that have a mean life of at least 500 hours when the production process is working properly.

denpristay [2]

Answer:

We conclude that the population mean light bulb life is at least 500 hours at the significance level of 0.01.

Step-by-step explanation:

We are given that a manufacturer produces light bulbs that have a mean life of at least 500 hours when the production process is working properly. The population standard deviation is 50 hours and the light bulb life is normally distributed.

You select a sample of 100 light bulbs and find mean bulb life is 490 hours.

Let $\mu$ = population mean light bulb life.

So, Null Hypothesis, $H_0$ : $\mu \geq$ 500 hours {means that the population mean light bulb life is at least 500 hours}

Alternate Hypothesis, $H_A$ : $\mu$ < 500 hours {means that the population mean light bulb life is below 500 hours}

The test statistics that would be used here One-sample z test statistics as we know about the population standard deviation;

T.S. = $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

where, $\bar X$ = sample mean bulb life = 490 hours

σ = population standard deviation = 50 hours

n = sample of light bulbs = 100

So, the test statistics = $\frac{490-500}{\frac{50}{\sqrt{100} } }$

= -2

The value of z test statistics is -2.

Now, at 0.01 significance level the z table gives critical value of -2.33 for left-tailed test.

Since our test statistic is higher than the critical value of z as -2 > -2.33, so we have insufficient evidence to reject our null hypothesis as it will not fall in the rejection region due to which we fail to reject our null hypothesis.

Therefore, we conclude that the population mean light bulb life is at least 500 hours.

7 0

3 years ago

I don’t know what to do with the 3 feet above the ground

Slav-nsk [51]

Answer:

3 seconds

Step-by-step explanation:

You want to set h(t)=3, then take the root such that t≠0. You would have:

3=3+48t−16t^2

Let's solve your equation step-by-step.

3=3+48t−16t2

Step 1: Simplify both sides of the equation.

3=−16t2+48t+3

Step 2: Subtract -16t^2+48t+3 from both sides.

3−(−16t2+48t+3)=−16t2+48t+3−(−16t2+48t+3)

16t2−48t=0

Step 3: Factor left side of equation.

16t(t−3)=0

Step 4: Set factors equal to 0.

16t=0 or t−3=0

t=0 or t=3

3 makes more sense than 0 because the ball can't have been in the air for 0 seconds.

So the ball was in the air for 3 seconds.

7 0

3 years ago

What quadrant is (0,-7) found in?

BaLLatris [955]

your answer is 1st quadrant!

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Have a good day <3

3 0

3 years ago

Y is a random variable that is distributed N(-16, 1.21). Find k such that Prob(-15.043 < Y ≤ k) = 0.1546. (Round your answer

IgorLugansk [536]

Transform Y to Z, which is distributed N(0, 1), using the formula

Y = µ + σZ

where µ = -16 and σ = 1.21.

Pr[-15.043 < Y ≤ k] = 0.1546

Pr[(-15.043 + 16)/1.21 < (Y + 16)/1.21 ≤ (k + 16)/1.21] = 0.1546

Pr[0.791 < Z ≤ (k + 16)/1.21] ≈ 0.1546

Pr[Z ≤ (k + 16)/1.21] - Pr[Z < 0.791] = 0.1546

Pr[Z ≤ (k + 16)/1.21] = 0.1546 + Pr[Z < 0.791]

Pr[Z ≤ (k + 16)/1.21] ≈ 0.1546 + 0.786

Pr[Z ≤ (k + 16)/1.21] ≈ 0.940

Take the inverse CDF of both sides (Φ(x) denotes the CDF itself):

(k + 16)/1.21 ≈ Φ⁻¹ (0.940) ≈ 1.556

Solve for k :

k + 16 = 1.21 • 1.556

k ≈ -14.118

8 0

3 years ago

Claire is on a business trip. She’ll be traveling from Liverpool, England, to Melbourne, Australia. The latitude value of Liverp

Alekssandra [29.7K]

Answer:

The change in latitude, Δφ, from Liverpool to Melbourne is 91.22° south

The change in longitude, Δλ, from Liverpool to Melbourne is 147.95° East

Step-by-step explanation:

The parameters given are;

The latitude of Liverpool is 53.41°

The longitude of Liverpool is -2.99°

The latitude of Melbourne is -37.81°

The longitude of Melbourne is 144.96°

The change in latitude from Liverpool to Melbourne = Δφ

Δφ = 53.41° - (-37.81°) = 53.41° + 37.81° = 91.22°

The change in latitude, Δφ, from Liverpool to Melbourne = 91.22° south

The change in longitude from Liverpool to Melbourne = Δλ

Δλ = -2.99° - 144.96° = -147.95°

Therefore the change in longitude from Liverpool to Melbourne = 147.95° East.

6 0

3 years ago

Read 2 more answers

Find the missing value to the nearest hundredth. cos (______) = 3/7