Homogeneous mixture a. silicon b. gasoline c. nickel

A particular brand of tires claims that its deluxe tire averages at least 50,000 miles before it needs to be replaced. From past

Vadim26 [7]

Answer:

We conclude that deluxe tire averages less than 50,000 miles before it needs to be replaced which means that the claim is not supported.

Step-by-step explanation:

We are given that a particular brand of tires claims that its deluxe tire averages at least 50,000 miles before it needs to be replaced. From past studies of this tire, the standard deviation is known to be 8000.

From the 28 tires surveyed, the mean lifespan was 46,500 miles with a standard deviation of 9800 miles.

Let $\mu$ = average miles for deluxe tires

So, Null Hypothesis, $H_0$ : $\mu \geq$ 50,000 miles {means that deluxe tire averages at least 50,000 miles before it needs to be replaced}

Alternate Hypothesis, $H_A$ : $\mu$ < 50,000 miles {means that deluxe tire averages less than 50,000 miles before it needs to be replaced}

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

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

where, $\bar X$ = sample mean lifespan = 46,500 miles

$\sigma$ = population standard deviation = 8000 miles

n = sample of tires = 28

So, test statistics = $\frac{46,500-50,000}{\frac{8000}{\sqrt{28} } }$

= -2.315

The value of the test statistics is -2.315.

Now at 5% significance level, the z table gives critical value of -1.6449 for left-tailed test. Since our test statistics is less than the critical value of z as -2.315 < -1.6449, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region due to which we reject our null hypothesis.

Therefore, we conclude that deluxe tire averages less than 50,000 miles before it needs to be replaced which means that the claim is not supported.

4 0

3 years ago

The population of a town is decreasing at a rate of 3.2% per year. In 2015, there were 14,250 people. What is the first year tha

notsponge [240]

The answer is D
you would set up an equation like this
14,250 x .032
this will give you how much the population is decreasing per year. Which is 456 people per year.
You then take 2015 and find the difference between that number and 2025 and do it with all of the other years too.
For example 2025-2015 is 10 years
You then take 10 x 456 to tell you how much the of population you lost in those 10 years. You will then take that number which is 4,560 and do 14,250-4,560 to get 9,650.

4 0

2 years ago

Amy wants to buy a pair of jeans that cost $65. Today the store is offering a straight discount of 25%. Calculate her savings an

galben [10]

Answer: she will save $16.25

Step-by-step explanation:

If you do 65 divided by 4 you will see how much 25 percent of 65

3 0

3 years ago

Read 2 more answers

Can someone tell me some word problems already solved? dividing and multiplying decimals and integers by 100,10 and 1000. I need

const2013 [10]

Answer:

wait im a little confused sorry but im going to try my best

Step-by-step explanation:

50x2=100. 5×2=10. 500x2=1,000

1,000÷10=100. 100÷10=10. 10,000÷10=1,000

5 0

3 years ago

The square pyramid has a volume of 768 cubic inches. The height equals 1/6x and the base is just x. What is the value of x ?

Lunna [17]

The volume for a pyramid is $V= \frac{1}{3} Bh$ , where B is the area of the base and h is the height. We are given the volume, and the base and height in terms of x. Our formula then looks like this: $768= \frac{1}{3} (x)( \frac{1}{6} x)$ . Simplifying the right side we have $768= \frac{1}{18} x^{2}$ . Multiply both sides by 18 to get rid of the fraction and we have $13824= x^{2}$ , so x = 117.575

5 0

3 years ago