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3 years ago

9

Jen wants to tile the floor of her kitchen. The floor is rectangular and measures 12 feet by 8 feet. If it costs $2.50 per squar

e foot for the materials, what is the total of the materials for tiling the kitchen floor?

1 answer:

Keith_Richards [23]3 years ago

8 0

I hope this helps you

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Cable Strength: A group of engineers developed a new design for a steel cable. They need to estimate the amount of weight the ca

KatRina [158]

Answer:

95% confidence interval for the mean breaking strength of the new steel cable is [763.65 lb , 772.75 lb].

Step-by-step explanation:

We are given that the engineers take a random sample of 45 cables and apply weights to each of them until they break. The mean breaking weight for the 45 cables is 768.2 lb. The standard deviation of the breaking weight for the sample is 15.1 lb.

Since, in the question it is not specified that how much confidence interval has be constructed; so we assume to be constructing of 95% confidence interval.

Firstly, the Pivotal quantity for 95% confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean breaking weight = 768.2 lb

s = sample standard deviation = 15.1 lb

n = sample of cables = 45

$\mu$ = population mean breaking strength

Here for constructing 95% confidence interval we have used One-sample t test statistics as we don't know about population standard deviation.

<u>So, 95% confidence interval for the population mean, </u> $\mu$ <u> is ;</u>

P(-2.02 < $t_4_4$ < 2.02) = 0.95 {As the critical value of t at 44 degree

of freedom are -2.02 & 2.02 with P = 2.5%}

P(-2.02 < $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ < 2.02) = 0.95

P( $-2.02 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $2.02 \times {\frac{s}{\sqrt{n} } }$ ) = 0.95

P( $\bar X-2.02 \times {\frac{s}{\sqrt{n} } }$ < $\mu$ < $\bar X+2.02 \times {\frac{s}{\sqrt{n} } }$ ) = 0.95

<u>95% confidence interval for</u> $\mu$ = [ $\bar X-2.02 \times {\frac{s}{\sqrt{n} } }$ , $\bar X+2.02 \times {\frac{s}{\sqrt{n} } }$ ]

= [ $768.2-2.02 \times {\frac{15.1}{\sqrt{45} } }$ , $768.2+2.02 \times {\frac{15.1}{\sqrt{45} } }$ ]

= [763.65 lb , 772.75 lb]

Therefore, 95% confidence interval for the mean breaking strength of the new steel cable is [763.65 lb , 772.75 lb].

3 0

3 years ago

Help me please and thank you!!!!!

olga nikolaevna [1]

Answer:

D-y=-3x+5

Step-by-step explanation:

Slope is -3x and y intercept is positive 5

3 0

3 years ago

Read 2 more answers

b) If a shopkeeper allows 20% discount and sells an article for Rs 200, find the marked price of the article.

zzz [600]

Answer:

250

Step-by-step explanation:

mp=sp+d%of mp

x = 200+20÷100×x

100x-20x = 20000

x= 250

3 0

2 years ago

melisa1 [442]

I think b is the correct answer or not

8 0

3 years ago

Six more than the quotient of a number and 4 is 3

Lera25 [3.4K]

We presume you want to find the number.

Let n represent the number.
6 + n/4 = 3 . . . . . . . 6 more than the quotient of a number and 4 is 3.
To solve this, we "undo" what is done to the number. First we undo the addition of 6 by adding its opposite, -6. We add -6 to both sides of the equation so the equal sign remains valid.
6 -6 +n/4 = 3 -6
n/4 = -3 . . . . . . . . simplify
Now, we need to undo the division by 4. We do that by multiplying by 4. Again, we must do that to both sides of the equation so the equal sign remains valid.
4(n/4) = 4(-3)
n(4/4) = -12
n = -12

The number is -12.

3 0

3 years ago