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likoan [24]
3 years ago
15

AARP reported on a study conducted to learn how long it takes individuals to prepare their federal income tax return (AARP Bulle

tin, April 2008). The data contained in the WEBfile named TaxReturn are consistent with the study results. These data provide the time in hours required for 40 individuals to complete their federal income tax returns. Using past years' data, the population standard deviation can be assumed known with σ = 11 hours.What is the 95% confidence interval estimate of the mean time it takes an individual to complete a federal income tax return? Round your answer to one decimal place.____ to ___ hoursReturn Preparation Time(Hours)35.330.537.426.513.049.928.844.061.60.540.534.947.936.624.139.847.818.536.639.214.537.340.549.345.528.319.55.652.641.445.339.033.729.414.540.133.736.95.633.7
Mathematics
1 answer:
Crank3 years ago
6 0

Answer:

Confidence interval: (30.1,36.9)

Step-by-step explanation:

We are given the following data set:

35.3,30.5,37.4,26.5,13.0,49.9,28.8,44.0,61.6,0.5,40.5,34.9,47.9,36.6,24.1,39.8,47.8,18.5,36.6,39.2,14.5,37.3,40.5,49.3,45.5,28.3,19.5,5.6,52.6,41.4,45.3,39.0,33.7,29.4,14.5,40.1,33.7,36.9,5.6,33.7

Formula:

\text{Standard Deviation} = \sqrt{\displaystyle\frac{\sum (x_i -\bar{x})^2}{n-1}}  

where x_i are data points, \bar{x} is the mean and n is the number of observations.  

Mean = \displaystyle\frac{\text{Sum of all observations}}{\text{Total number of observation}}

Mean =\displaystyle\frac{1339.9}{40} = 33.5

S.D = 11(given)

n = 40

Confidence interval:

\mu \pm z_{critical}\frac{\sigma}{\sqrt{n}}

Putting the values, we get,

z_{critical}\text{ at}~\alpha_{0.05} = 1.96

33.5 \pm 1.96(\frac{11}{\sqrt{40}} ) = 6.34 \pm 3.4 = (30.1,36.9)

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96

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2 years ago
Malachy, Sushil and Fiona share some sweets in the ratio 7:1:1. Malachy gets 90 more sweets than Fiona. How many sweets does Sus
VashaNatasha [74]

Answer:

15

Step-by-step explanation:

Fiona (F) = Sushi (S)

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3 0
3 years ago
You have a wire that is 38 cm long. you wish to cut it into two pieces. one piece will be bent into the shape of a square. the o
erica [24]
Circumference + perimeter =38
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(38-x) is perimeter
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6 0
3 years ago
The table shows the charges for using an internet service. Nicholas use the internet service for 16 hours and 40 Minutes last mo
yanalaym [24]

Answer:

<u>A. Nicholas will have to pay less using plan A</u>

<u>B. He will pay US$ 4 less than plan B</u>

Step-by-step explanation:

Let's compare how much Nicholas will pay on internet service in Plan A and plan B, after using it 16 hours and 40 minutes.

Plan A

Up to 10 hours = US$ 6

Every subsequent 1/2 hour: $1

10 hours + 14 (1/2 hour)

<u>Nicholas will pay 6 + 14 * 1 = US$ 20</u>

Plan B

Up to 12 hours = US$ 4

Every subsequent 1/2 hour: $2

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<u>Nicholas will pay 4 + 2 * 10 = 24</u>

7 0
3 years ago
HELP HELP HELP!!!!!!!!!!!!!!!!!!!!!!!!!
bagirrra123 [75]
A, C, and D
Hope this helps :)
Can I have brainliest
4 0
2 years ago
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