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4 years ago

Unit 2 EquationsEvaluate the expression if a=2 b=4 c=8 ac= ? *○16○10○8○4

Mathematics

2 answers:

Masteriza [31]4 years ago

6 0

Answer:

Step-by-step explanation:

Substitute the numbers or the variables, and we know that anything next to a variable, both are multiplied together.

So, multiply both numbers:

a=2------> 2*8=16

c=8----^

kvv77 [185]4 years ago

5 0

Answer:

Explanation:

a = 2

c = 8

2 · 8 = 16

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A sanitation department is interested in estimating the mean amount of garbage per bin for all bins in the city. In a random sam

soldi70 [24.7K]

Answer:

a) $52.8-2.02\frac{3.9}{\sqrt{40}}=51.554$

b) $52.8+2.02\frac{3.9}{\sqrt{40}}=54.046$

c) $52.8-2.71\frac{3.9}{\sqrt{40}}=51.129$

d) $52.8+2.71\frac{3.9}{\sqrt{40}}=54.471$

e) Yes, depends of the confidence level.

At 95 % of confidence the value 54.1985 pounds is not included on the interval. At 5% of significance the statement is FALSE.

At 99 % of confidence the value 54.1985 pounds is included on the interval. So at 1% of significance the statement is TRUE.

Step-by-step explanation:

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".

$\bar X =52.8$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s=3.9 represent the sample standard deviation

n=40 represent the sample size

a) What is the lower limit of the 95% interval? Give your answer to three decimal places

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

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

In order to calculate the mean and the sample deviation we can use the following formulas:

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=40-1=39$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,39)".And we see that $t_{\alpha/2}=2.02$

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

$52.8-2.02\frac{3.9}{\sqrt{40}}=51.554$

b) What is the upper limit of the 95% interval? Give your answer to three decimal places

$52.8+2.02\frac{3.9}{\sqrt{40}}=54.046$

So on this case the 95% confidence interval would be given by (51.554;54.046)

c) What is the lower limit of the 99% interval? Give your answer to three decimal places

Since the Confidence is 0.99 or 99%, 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: "=-T.INV(0.005,39)".And we see that $t_{\alpha/2}=2.71$

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

$52.8-2.71\frac{3.9}{\sqrt{40}}=51.129$

d) What is the upper limit of the 99% interval? Give your answer to three decimal places

$52.8+2.71\frac{3.9}{\sqrt{40}}=54.471$

So on this case the 99% confidence interval would be given by (51.129;54.471)

e) Consider the claim that the mean amount of garbage per bin is 54.1985 pounds. Is the following statement true or false? The decision about the claim would depend on whether we use a 95% or 99% confidence interval: True/False

Yes, depends of the confidence level.

At 95 % of confidence the value 54.1985 pounds is not included on the interval. At 5% of significance the statement is FALSE.

At 99 % of confidence the value 54.1985 pounds is included on the interval. So at 1% of significance the statement is TRUE.

3 0

4 years ago

Need help in this please

Alona [7]

Hmmm this is a little hard I believe c

8 0

3 years ago

I need help! Please please please please

blsea [12.9K]

I'm pretty sure that the answer to the fudge cakes is 8 friends

7 0

3 years ago

Aidan has $65 in his bank account. His brother Michael also has a bank account. They want to calculate the amount of money in bo

Aleks [24]

Answer:

m, the amount of money in Michael's bank account

t, the total between the two bank accounts

the equation could be 65+m= t

hope this helps :)

4 0

3 years ago

Help QUICK please and thank youuu :))

telo118 [61]

Step 1: Simplify both sides of the equation.

28 = −7 /2 x

Step 2: Flip the equation.

−7 /2 x = 28

Step 3: Multiply both sides by 2/(-7).

( 2 /−7 )*( −7 /2 x) = ( 2 /−7 )*(28)

x=−8

Answer:

x=−8

4 0

4 years ago

Read 2 more answers

Unit 2 EquationsEvaluate the expression if a=2 b=4 c=8 ac= ? *○16○10○8○4​

Unit 2 EquationsEvaluate the expression if a=2 b=4 c=8 ac= ? *○16○10○8○4