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3 years ago

Evaluate 7r-15/8 when r=3 and 8=5

Mathematics

2 answers:

Natali [406]3 years ago

8 0

Answer:

Step-by-step explanation:

multiply 7 and 3

reduce 15/5 to 3

subtract 21-3

statuscvo [17]3 years ago

6 0

Answer:

Explanation:

7(3)-15/5

21-15/5

21-3=18

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The mean waiting time at the drive-through of a fast-food restaurant from the time the food is ordered to when it is received is

alexira [117]

Answer:

a) And if we replace we got: $\bar X= 78$

$s = 15.391$

b) $78-3.25\frac{15.391}{\sqrt{10}}=62.182$

$78-3.25\frac{15.391}{\sqrt{10}}=93.818$

So on this case the 99% confidence interval would be given by (62.182;93.818)

Step-by-step explanation:

Dataset given: 109 67 58 76 65 80 96 86 71 72

Part a

For this case we can calculate the sample mean with the following formula:

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

And if we replace we got: $\bar X= 78$

And the deviation is given by:

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

And if we replace we got $s = 15.391$

Part b

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:

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

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(0.005,9)".And we see that $t_{\alpha/2}=3.25$

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

$78-3.25\frac{15.391}{\sqrt{10}}=62.182$

$78-3.25\frac{15.391}{\sqrt{10}}=93.818$

So on this case the 99% confidence interval would be given by (62.182;93.818)

8 0

2 years ago

Mariko has an 1:80 scale-drawing of the floor plan of her house. On the floor plan, the dimensions of her rectangular living roo

NNADVOKAT [17]

Answer:1 inch is actually 80 inch so:

1 7/8 x 80 is true length of side 1 and

2 1/2 x 80 is true length of side 2 of room

Step-by-step explanation:

the area is side 1 x side 2 in sq inches

then change square inches to square feet for your final answer

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2 years ago

Read 2 more answers

Convert 17/34 to decimal using long division

Agata [3.3K]

Answer:

Step-by-step explanation:

$\frac{17}{34}=\frac{1}{2}=0.5$

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2 years ago

What's the mean median and mode of 8,2,3,5,7

Alex_Xolod [135]

Answer:

mean:25 median:3 there is no mode

Step-by-step explanation:

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2 years ago

Which statement implies that A and B are independent events?

STatiana [176]

Answer:

$P(A \cap B) = P(A)P(B)$

Step-by-step explanation:

Independent events:

If two events, A and B are independent, the probability of both A and B happening is the same as the probability of A happening multiplied by the probability of B happenings, that is:

$P(A \cap B) = P(A)P(B)$

In this question:

The statement is $P(A \cap B) = P(A)P(B)$

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2 years ago

Evaluate 7r-15/8 when r=3 and 8=5​

Evaluate 7r-15/8 when r=3 and 8=5