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abruzzese [7]
3 years ago
5

Grace earns $7 for each car she washes. She always saves $25 for her weekly earnings. This week, she wants to have at least $65

in spending money. How many cars must wash?
Mathematics
1 answer:
n200080 [17]3 years ago
7 0
In order to figure out how many cars she must wash, first you should figure out how much money total you need.  This week, she needs $25 for her weekly earnings + $65 for spending money = $90.  Then you divide the total amount of money, $90, by 7.  The answer is 12.8, but because you can't wash 12.8 cars, the answer is 13.
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GreenBeam Ltd. claims that its compact fluorescent bulbs average no more than 3.50 mg of mercury. A sample of 25 bulbs shows a m
Harrizon [31]

Answer:

(a) Null Hypothesis, H_0 : \mu \leq 3.50 mg  

     Alternate Hypothesis, H_A : \mu > 3.50 mg

(b) The value of z test statistics is 2.50.

(c) We conclude that the average mg of mercury in compact fluorescent bulbs is more than 3.50 mg.

(d) The p-value is 0.0062.

Step-by-step explanation:

We are given that Green Beam Ltd. claims that its compact fluorescent bulbs average no more than 3.50 mg of mercury. A sample of 25 bulbs shows a mean of 3.59 mg of mercury. Assuming a known standard deviation of 0.18 mg.

<u><em /></u>

<u><em>Let </em></u>\mu<u><em> = average mg of mercury in compact fluorescent bulbs.</em></u>

So, Null Hypothesis, H_0 : \mu \leq 3.50 mg     {means that the average mg of mercury in compact fluorescent bulbs is no more than 3.50 mg}

Alternate Hypothesis, H_A : \mu > 3.50 mg     {means that the average mg of mercury in compact fluorescent bulbs is more than 3.50 mg}

The test statistics that would be used here <u>One-sample z test</u> <u>statistics</u> 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 mg of mercury = 3.59

            \sigma = population standard deviation = 0.18 mg

            n = sample of bulbs = 25

So, <em><u>test statistics</u></em>  =  \frac{3.59-3.50}{\frac{0.18}{\sqrt{25} } }

                               =  2.50

The value of z test statistics is 2.50.

<u>Now, P-value of the test statistics is given by;</u>

         P-value = P(Z > 2.50) = 1 - P(Z \leq 2.50)

                                             = 1 - 0.9938 = 0.0062

<em />

<em>Now, at 0.01 significance level the z table gives critical value of 2.3263 for right-tailed test. Since our test statistics is more than the critical values of z, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region due to which </em><em><u>we reject our null hypothesis</u></em><em>.</em>

Therefore, we conclude that the average mg of mercury in compact fluorescent bulbs is more than 3.50 mg.

6 0
3 years ago
10 points plz help thanks
ryzh [129]

Answer:

b

Step-by-step explanation:

3 0
3 years ago
Plzz help me out look at the pic
Nookie1986 [14]

Answer:

(B) 10

Step-by-step explanation:

Rate of change is basically slope

So the slope here is 10/1 so the rate of change is 10

6 0
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The answer to this is 7
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If the frequency of a sound decreases, what happens to the wavelength?
madam [21]

Answer: The wavelength increases

Step-by-step explanation:

As frequency increases, wavelength decreases. Frequency and wavelength are inversely proportional. This basically means that when the wavelength is increased, the frequency decreases and vice versa.

Hope that this helps! Have a great day!

7 0
2 years ago
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