Aconsumer claims that the mean lifetime of a brand of fluorescent bulbs is less than1500 hours. she selects 25 bulbs and finds the mean lifetime to be 1480 hours with the standard deviation of 80 hours. if you were to test the consumer's claimat the 0.05 significance level, what would you conclude?

We conclude that the mean lifetime of a brand of fluorescent bulbs is equal to 1500 hours.

Step-by-step explanation:

We are given the following in the question:  

Population mean, μ = 1500 hours

Sample mean, = 1480 hours

Sample size, n = 25

Alpha, α = 0.05

Sample standard deviation, s = 80 hours

First, we design the null and the alternate hypothesis

We use one-tailed(left) t test to perform this hypothesis.

Formula:

Putting all the values, we have

Now,

Since,                    

We fail to reject the null hypothesis and accept the null hypothesis.

We conclude that the mean lifetime of a brand of fluorescent bulbs is equal to 1500 hours.

answer:   28.56 feet (approx)

step-by-step explanation:

since, triangle abc has measure of angle c equal to 55 degrees, measure of angle abc equal to 90 degrees, and length of bc equal to 20 feet.

we have to find out the measurement of segment ab.

therefore, tan 55° =

but bc = 20 feet.

⇒ tan 55 ° =  

⇒ ab = 20 × tan 55 °

⇒ ab = 20 × 1.42814800674

⇒ ab = 28.5629601348   ≈ 28.56 feet

b. y = 4x - 2

step-by-step explanation:

to find a parallel equation to an equation, make sure both equations have the same slope but different y-intercepts.

y = 4x + 1

4 = slope

1 = y-intercept

y = 4x - 2

4 = slope

-2 = y-intercept

they both have the same slope but different y-intercepts, so, b. is the correct answer.

and to check your work, you can graph both equations. : )