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3 years ago

13

Use the provided ruler. Suppose you recreate the drawing so that it has a scale of 1 cm : 4 m. What will the length and width of

the new scale drawing be?

1 answer:

Burka [1]3 years ago

5 0

I think the answer is 1 cm: 2 m

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What is 43,000,000,000 in scientific notation

andrey2020 [161]

I think the scientific notation would be...

4.3 x 10^10

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3 years ago

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How to find if a problem is proportional or non proportional relationship

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3 years ago

1. Mark is six years older than his brother Sam. The sum of their ages is 30. What a be Sam's age. Set up and solve an equation

barxatty [35]

Answer:

1) Sam's age = a = 12

Mark's age = 18

2) Number of tickets Mandy sells = N = 12

Number of tickets Alonso sells = 31

3) Number of points Elena scores = a = 12

Number of points Karla scores = 24

Number of points Faye scores = 42

Faye scores more points!

Step-by-step explanation:

1) Let a represent Sam's age

Mark's age = a + 6

Sum of their ages = 30

a + (a + 6) = 30

2a + 6 = 30

2a = 24

a = 12 year old

a + 6 = 12 + 6 = 18 year old

Sam's age = 12

Mark's age = 18

2) Let N represent the number of tickets that Mandy sells

Alonso sells five tickets less than three times Mandy sells, that is equal to (3N - 5) tickets.

Total number of tickets sold = 43

N + 3N - 5 = 43

4N = 48

N = 12 tickets

3N - 5 = 36 - 5 = 31 tickets

Number of tickets Mandy sells = N = 12

Number of tickets Alonso sells = 31

3) Let the number of points Elena scores = a

Number of points Karla scores = 2a

Number of points Faye scores = a + 30

Total number of points = 114

a + 2a + a + 30 = 114

4a = 114 - 30 = 84

4a = 84

a = 12 points

2a = 24 points

a + 30 = 42 points

Number of points Elena scores = a = 12

Number of points Karla scores = 24

Number of points Faye scores = 42

Since 42>24, Faye evidently scores more points than Carla.

3 0

4 years ago

What is the distance between the points(-5,-1) and (-2,-6) ? Round to the nearest tenth if necessary.

Oksana_A [137]

Answer:

5.8

Step-by-step explanation:

the distance formula is

d =sqrt( (x2-x1)^2 + (y2-y1)^2 )

= sqrt ( (-5 - -2) ^2 + (-1 - -6)^2 )

= sqrt( (-5 +2) ^2 + (-1 +6)^2 )

= sqrt( (-3) ^2 + (5)^2 )

= sqrt( 9+25)

= sqrt(34)

=5.830951895

Rounding to the nearest tenth

5.8

3 0

4 years ago

Read 2 more answers

The mean weight of 10 randomly selected newborn babies at a local hospital is 7.14 lbs and the standard deviation is 0.87 lbs. A

sergejj [24]

Answer:

a) $ME= 1.83 \frac{0.87}{\sqrt{10}}=0.5035$

b) 90% of all samples of size 10 have sample means within 0.5035 of the population mean.

c) The 90% confidence interval would be given by (6.636;7.643)

d) Yes, since the lower limit for the 90% confidence interval is higher than the value of 6.5 we can conclude that the true mean is significantly higher than 6.5 at 10% of significance. (6.636>6.5)

e) If we increase the confidence level that implies increase the margin of error. Since with more confidence level the value for the critical value $t_{\alpha/2}$ increase. So then the new interval would be wider than the original.

Step-by-step explanation:

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".

$\bar X=7.14$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s=0.87 represent the sample standard deviation

n=10 represent the sample size

Part a

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

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

And the margin of error is given by:

$ME= t_{\alpha/2}\frac{s}{\sqrt{n}}$

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

$df=n-1=10-1=9$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.05,9)".And we see that $t_{\alpha/2}=1.83$

$ME= 1.83 \frac{0.87}{\sqrt{10}}=0.5035$

Part b

90% of all samples of size 10 have sample means within 0.5035 of the population mean.

Part c

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

$7.14-1.83\frac{0.87}{\sqrt{10}}=6.637$

$7.14+1.83\frac{0.87}{\sqrt{10}}=7.643$

So on this case the 90% confidence interval would be given by (6.636;7.643)

Part d

Yes, since the lower limit for the 90% confidence interval is higher than the value of 6.5 we can conclude that the true mean is significantly higher than 6.5 at 10% of significance. (6.636>6.5)

Part e

If we increase the confidence level that implies increase the margin of error. Since with more confidence level the value for the critical value $t_{\alpha/2}$ increase. So then the new interval would be wider than the original.

7 0

4 years ago