Can somebody help me with my math?

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

PLZ HELP HURRY PLZ!!!!!!!!!!!!!!!!

Mademuasel [1]

Answer:

D

Step-by-step explanation:

You subtract the "-6" from the y, and you get +6 (which eliminates A and B). You subtract the "-2" from the x, and you get +2 (which eliminates C)

4 0

2 years ago

A person made 4 blankets. each blanket used 180 inches of ribbon for the border. How many yards of ribbon did the person use for

irina [24]

I think it's 720 because 180x4=720

6 0

3 years ago

Read 2 more answers

What is the equation of the line which has a gradient of 2 and passes through the point (1,4)

timofeeve [1]

Answer:

Y= 2x+2

Step-by-step explanation:

line equation is y=mx +c

m is the gradient = 2

We are given an x and y value

X= 1
y= 4

substitute that into the equation:

4= 2(1) +c

2=c

Put all the equation together:

Y= 2x+2

5 0

2 years ago

If ∠WOZ and ∠WOX are supplementary angles and ∠WOX and ∠XOY are complementary angles, then what is the value of x and m∠XOY?

omeli [17]

Answer:

D.x = 6; m∠XOY = 18°

Step-by-step explanation:

Supplementary angles add to 180 and complementary angles add to 90

∠WOZ + ∠WOX = 180

108 + ∠WOX = 180

∠WOX + ∠XOY = 90

∠WOX + 3x = 90

∠WOX = 90 -3x

Replace WOX in the first equation

108 + ∠WOX = 180

108 + 90 -3x = 180

Combine like terms

198 -3x = 180

Subtract 198 from each side

-3x = 180-198

-3x = -18

Divide by -3

-3x/-3 = -18/-3

x = 6

∠XOY = 3x = 3*6 = 18

5 0

2 years ago