Mathematics : asked on mrus
 02.07.2021

A polling company is trying to estimate the percentage of adults that consider themselves happy. A confidence interval based on a sample size of 180 has a larger than desired margin of error. The company wants to conduct another poll and obtain another confidence interval of the same level but reduce the error to one-third the size of the original sample. How many adults should they now interview

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24.06.2023, solved by verified expert
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They should interview 1620 adults now.

Step-by-step explanation:

Margin of error of a confidence interval:

The margin of error of a confidence interval has the following format:

A polling company is trying to estimate the percentage, №17886193, 02.07.2021 05:44

In which z is related to the confidence level, A polling company is trying to estimate the percentage, №17886193, 02.07.2021 05:44 is the standard deviation of the population and n is the size of the sample.

In this question:

z wont change, neither will A polling company is trying to estimate the percentage, №17886193, 02.07.2021 05:44

We want to increase n as such the margin of error is reduced to one third.

We have that the margin of error is inversely proportional to the square root of the size of the sample, which means that for the margin of error to be reduced to one third, the sample size has to be multiplied by A polling company is trying to estimate the percentage, №17886193, 02.07.2021 05:44. So

180*9 = 1620

They should interview 1620 adults now.

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Mathematics
Step-by-step answer
P Answered by PhD

They should interview 1620 adults now.

Step-by-step explanation:

Margin of error of a confidence interval:

The margin of error of a confidence interval has the following format:

M = z\frac{\sigma}{\sqrt{n}}

In which z is related to the confidence level, \sigma is the standard deviation of the population and n is the size of the sample.

In this question:

z wont change, neither will \sigma

We want to increase n as such the margin of error is reduced to one third.

We have that the margin of error is inversely proportional to the square root of the size of the sample, which means that for the margin of error to be reduced to one third, the sample size has to be multiplied by 3^2 = 9. So

180*9 = 1620

They should interview 1620 adults now.

Mathematics
Step-by-step answer
P Answered by PhD

For 1 flavor there are 9 topping

Therefore, for 5 different flavors there will be 5*9 choices

No of choices= 5*9

=45 

Mathematics
Step-by-step answer
P Answered by PhD

For every 8 cars there are 7 trucks

Therefore,

Cars:Truck=8:7

Answer is B)8:7

Mathematics
Step-by-step answer
P Answered by PhD

F=ma

where F=force

m=mass

a=acceleration

Here,

F=4300

a=3.3m/s2

m=F/a

    =4300/3.3

    =1303.03kg

Mathematics
Step-by-step answer
P Answered by PhD

The answer is in the image 

The answer is in the image 
Mathematics
Step-by-step answer
P Answered by PhD

The solution is given in the image below

The solution is given in the image below
Mathematics
Step-by-step answer
P Answered by PhD

Speed=Distance/time

Here,

distance=15m

time=1sec

speed=15/1=15m/sec

Distance=Speed*time

time=15min=15*60sec=900sec

Distance travelled in 15 min=15*900=13,500m

=13500/1000 km=13.5Km

Mathematics
Step-by-step answer
P Answered by PhD

Salesperson will make 6% of 1800

=(6/100)*1800

=108

Salesperson will make $108 in $1800 sales

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