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3 years ago

Solve the inequality 2x – 5 > 7

Mathematics

1 answer:

ziro4ka [17]3 years ago

7 0

2x – 5 > 7
Add 5 to both sides
2x > 12
Divide 2 on both sides
Final Answer: x > 6

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The area of a triangle is .5 x base x height

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3 years ago

PLEASE HELP BRAINLIEST AND POINTS!!

Alex_Xolod [135]

Answer:

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Step-by-step explanation:

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3 years ago

Read 2 more answers

Bob Nale is the owner of Nale’s Quick Fill. Bob would like to estimate the mean number of gallons of gasoline sold to his custom

ira [324]

Answer:

a) The best estimator for the population mean is given by the sample mean $\hat \mu = \bar X = 5.70$

b) The 99% confidence interval would be given by (4.969;6.431)

c) We are 99% confident that the true mean for th number of gallons of gasoline sold to his customers is between 4.969 and 6.431.

Step-by-step explanation:

1) Previous concepts

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 means 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.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

$\sigma=1.9$ represent the population standard deviation

n=45 represent the sample size

2) Part a

The best estimator for the population mean is given by the sample mean $\hat \mu = \bar X = 5.70$

3) Part b. Develop a 99 percent confidence interval for the population mean.

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.005,0,1)".And we see that $z_{\alpha/2}=2.58$

Now we have everything in order to replace into formula (1):

$5.7-2.58\frac{1.9}{\sqrt{45}}=4.969$

$5.7+2.58\frac{1.9}{\sqrt{45}}=6.431$

So on this case the 99% confidence interval would be given by (4.969;6.431)

4) Part c. Interpret the meaning of part (b).

On this case we can say this: We are 99% confident that the true mean for th number of gallons of gasoline sold to his customers is between 4.969 and 6.431.

4 0

3 years ago

How many decibels is this? show work

slavikrds [6]

Answer:

115 dB

Explanation:

1. Given equation:

$\beta =10log(\frac{I}{I_0})\\\\ I_0=10^{-12}W/m^2$

2. Given intensity:

$I=0.315W/m^2$

3. Decibels

$\beta =10log(0.315/10^{-12})\\ \\ \beta =10log(315,000,000,000)\\ \\ \beta =10(11.498)=114.98\approx 115$

4 0

3 years ago

The average human gestation period is 270 days with a standard deviation of 9 days. The period is normally distributed. What is

Anna35 [415]

Answer:

Probability that a randomly selected woman's gestation period will be between 261 and 279 days is 0.68.

Step-by-step explanation:

We are given that the average human gestation period is 270 days with a standard deviation of 9 days. The period is normally distributed.

Firstly, Let X = women's gestation period

The z score probability distribution for is given by;

Z = $\frac{ X - \mu}{\sigma}$ ~ N(0,1)

where, $\mu$ = average gestation period = 270 days

$\sigma$ = standard deviation = 9 days

Probability that a randomly selected woman's gestation period will be between 261 and 279 days is given by = P(261 < X < 279) = P(X < 279) - P(X $\leq$ 261)

P(X < 279) = P( $\frac{ X - \mu}{\sigma}$ < $\frac{279-270}{9}$ ) = P(Z < 1) = 0.84134

P(X $\leq$ 261) = P( $\frac{ X - \mu}{\sigma}$ $\leq$ $\frac{261-270}{9}$ ) = P(Z $\leq$ -1) = 1 - P(Z < 1)

= 1 - 0.84134 = 0.15866

Therefore, P(261 < X < 279) = 0.84134 - 0.15866 = 0.68

Hence, probability that a randomly selected woman's gestation period will be between 261 and 279 days is 0.68.

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3 years ago