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2 years ago

Find the semi perimeter of a triangle with sides 9cm 12 cm and 30 cm

Mathematics

1 answer:

alexgriva [62]2 years ago

7 0

Answer:

Step-by-step explanation:

$= \frac{9 + 12 + 30}{2}cm \\ = \frac{51}{2}cm \\ 25.5cm$

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Judy and Ramey together have 42 stuffed animals. Judy has 12 fewer animals than Ramey. How many stuffed animals does each girl h

Art [367]

Answer: Ramey has 27 and Judy has 15

Step-by-step explanation:

Just bc 27 + 15 is 42

7 0

1 year ago

Tom and jerry have to stuff and seal 63 envelopes for a new marketing campaign. Jerry can stuff and seal 15 envelopes alone in 2

zheka24 [161]

Chile—. Ion understand, good luck tho.....

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2 years ago

A human body while sleeping generates about 300 BTUs of body heat per hour. If two people are sleeping in a bedroom that is 15 f

Katarina [22]

Given:
one person can produce:
E = <span>300 BTUs of body heat per hour
dimensions of the bedroom is:
V = </span><span>15 ft × 12 ft × 10 ft

required: is the energy per volume if 2 persons sleeps in 7 hours
let T be the total energy produce per volume

T = (</span><span>300 BTU per hour per person) ( 7 hours) ( 2 person) / ( </span> <span>15 ft × 12 ft × 10 ft)

T = 2.3 BTU / ft^3</span>

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1 year ago

Consider the following random sample from a normal population: 14, 10, 13, 16, 12, 18, 15, and 11. What is the 95% confidence in

seraphim [82]

Answer:

$13.625-2.365\frac{2.669}{\sqrt{8}}=11.393$

$13.625+2.365\frac{2.669}{\sqrt{8}}=15.857$

So on this case the 95% confidence interval would be given by (11.393;15.857)

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".

Data: 14, 10, 13, 16, 12, 18, 15, 11

We can calculate the sample mean and deviation with the following formulas:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

$s = \sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}$

$\bar X=13.625$ represent the sample mean

$\mu$ population mean (variable of interest)

s=2.669 represent the sample standard deviation

n=8 represent the sample size

Calculate the confidence interval

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

$df=n-1=8-1=7$

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(0.025,7)".And we see that $t_{\alpha/2}=2.365$