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2 years ago

10

Will mark brainliest please help Debbie notices that the amount owed on her monthly heating bill varies inversely with the avera

ge outdoor temperature. Last month the average outdoor temperature was 35°F, and her bill was $210. If this month's average outdoor temperature is 40°F, what can Debbie expect her bill to be?

1 answer:

Alekssandra [29.7K]2 years ago

7 0

Answer:

The bill is $1837.5

Step-by-step explanation:

Given

$B = Bills$

$T = Temperature$

$B\ \alpha\ \frac{1}{T}$ --- The variation

T = 35; when B = 210

Required

Find B when T = 40

$B\ \alpha\ \frac{1}{T}$

Express as an equation

$B = \frac{k}{T}$

Make k the subject

$k = BT$

<em>T = 35; when B = 210</em>

$k = 35 * 210$

$k = 7350$

When T = 40, we have:

$k = BT$

$7350 = B * 40$

Make B the subject

$B = \frac{7350}{4}$

$B = 1837.5$

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Step-by-step explanation:

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6 is the ones place.

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Answer:

The 98% confidence interval for the variance in the pounds of impurities would be $8.400 \leq \sigma^2 \leq 39.827$ .

Step-by-step explanation:

1) Data given and notation

$s^2 =16$ represent the sample variance

s=4 represent the sample standard deviation

$\bar x$ represent the sample mean

n=20 the sample size

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A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population mean or variance lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

The Chi square distribution is the distribution of the sum of squared standard normal deviates .

2) Calculating the confidence interval

The confidence interval for the population variance is given by the following formula:

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And replacing into the formula for the interval we got:

$\frac{(19)(16)}{36.191} \leq \sigma^2 \leq \frac{(19)(16)}{7.633}$

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So the 98% confidence interval for the variance in the pounds of impurities would be $8.400 \leq \sigma^2 \leq 39.827$ .

7 0

3 years ago

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Answer:

Step-by-step explanation:

It's D.

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