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sweet [91]
3 years ago
5

The manager of a grocery store has selected a random sample of 100 customers. The average length of time it took these 100 custo

mers to check out was 3.0 minutes. It is known that the standard deviation of the checkout time is 1 minute. The 95% confidence interval for the average checkout time for all customers is ________?
Mathematics
1 answer:
SSSSS [86.1K]3 years ago
4 0

Answer:

The 95% confidence interval would be given by (2.804;3.196)    

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=3.0 represent the sample mean  

\mu population mean (variable of interest)

\sigma=1 represent the population standard deviation

n=100 represent the sample size  

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

\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}   (1)

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: "=-NORM.INV(0.025,0,1)".And we see that z_{\alpha/2}=1.96

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

3.0-1.96\frac{1}{\sqrt{100}}=2.804    

3.0+1.96\frac{1}{\sqrt{10}}=3.196

So on this case the 95% confidence interval would be given by (2.804;3.196)    

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Barbara purchased a home entertainment center for $2,665 using an 18-month deferred payment plan with an interest rate of 24.36%
Andre45 [30]

Answer:

P = $ 144.99

Step-by-step explanation:

Given data:

cost of home entertainment center is $2665

duration of deferred payment plan is 18 month

interest rate is 24.36%

Total amount to be paid is = P(1+ \frac{R}{100})^t

                                          = 2665 (1+ \frac{24.36}{100})^1.5

A = 3695.88

From the information in the questioon this amount is to be paid in 3 year . Thus we have

Monthly payment is =

P = \frac{r(Pv)}{1 - (1+ r)^{-n}}

p = monthly payment

Pv = present value = 3695.88

r =rate per period = \frac{24.36}{12} = 0.020

n = number of period = 12\times 3 = 36

plugging all value in the above formula

P = \frac{0.020\times 3695.88}{1 - (1+0.020)^{-36}}

P = $ 144.99

5 0
3 years ago
Suppose that G(X) = F(x+ 9). Which statement best compares the graph of
coldgirl [10]

Answer: Option D

Step-by-step explanation:

By definition if we have a function F (x) and perform a transformation of the form

G (x) = F (x + c)

Then it is true that:

If c is negative the graph of G(x) will be equal to the graph of F(x) displaced horizontally c units to the right

If c is positive, the graph of G(x) will be equal to the graph of F(x) displaced horizontally c units to the left.

Note that in this case the transformation is:

G (x) = F (x + 9)

Then c = 9 and c> 0

Therefore the graph of G(x) will be equal to the graph of F(x) displaced horizontally <em>9 units to the left</em>

The answer is the option D.

5 0
3 years ago
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Approximately how many inches are in 2500 millimeters? Given 1 in = 2.54 cm, 1 ft = .3048 m, 1 mi = 1.61 km.
love history [14]
Let's begin with 2500 mm and convert this to cm.  

2500 mm = 250 cm

Next, convert 250 cm to inches.  Recall that 1 inch = 2.54 cm.

Then (250 cm)(1 inch) / (2.54 cm) = (250 cm) (1 in)/ (2.54 cm)

= (250/2.54) inches = ? inches
7 0
3 years ago
What is the geometrick mean of 27 and 8 with the pothagereom theorem
enyata [817]

Answer:

x = 6√6

Step-by-step explanation:

27/x = x/8

x² = 27 × 8

x = √(27 × 8)

x = √(9 × 4 × 6)

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5 0
2 years ago
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Tom [10]
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B. Isosceles: An isosceles triangle has two sides that are equal. 45 and 45 are equal, therefore, this answer is: Correct!

C. Scalene: A scalene triangle has three unequal sides, therefore, this answer is incorrect.

D. Obtuse: An obtuse triangle has one angle that is more than 90 degrees, therefore, since 45 and 45 equal 90 already, this answer is: incorrect.

E. Right: A right triangle has one right angle (angle that equals 90 degrees) since 45 + 45 = 90, and 90 + 90 = 180, this answer is: Correct!

F. Equiangular: This last choice is practically the same as the first, therefore the answer is: incorrect.

The two correct answers are: B Isosceles, and E Right!
4 0
3 years ago
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