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A sample of 16small bags of the same brand of candies was selected. Assume that the population distribution of bag

weights is normal. The weight of each bag was then recorded. The mean weight was two ounces with a standard deviation

of 0.12ounces. The population standard deviation is known to be0.1 ounce.

a.i.x̄=________ii.σ=________iii.sx=________

b. In words, define the random variableX.

c. In words, define the random variableXÌ„.

d. Which distribution should you use for this problem? Explain your choice.

e. Construct a 90%confidence interval for the population mean weight of the candies.

i. State the confidence interval.

ii. Sketch the graph.

iii. Calculate the error bound.

f. Construct a 98%confidence interval for the population mean weight of the candies.

i. State the confidence interval.

ii. Sketch the graph.

iii. Calculate the error bound.

g. In complete sentences, explain why the confidence interval in partf is larger than the confidence interval in part e.

h. In complete sentences, give an interpretation of what the interval in part fmeans.

Short Answer

Expert verified

(a) The result of :

I. x¯=2

II. σ=0.12

III. n=16

(b) xis the weight of one candy bag.

(c) The average weight of 16 bags of candy was calculated from a sample of 16 bags having mean is X¯,

(d) The problem is solved using the normal distribution localid="1651751618944" N2,0.1216.

(e) the result of

i.localid="1651751622794" CI=(1.9589,2.0411)

ii. The graph is drawn

iii. the result we have localid="1651751626293" EBM=0.0411.

(f) The results of

i. we get localid="1651751629945" CI=(1.9418,2.0582)

ii. The graph is drawn

iii. the final result we see EBM=0.0582

(g)The region defined by the normal curve is used to compute the confidence interval. If all of the limits remain the same, the level of confidence remains the same. The level of confidence associated with the area then rises.

(h) Because of the same size error constraint, the confidence level would decrease for the same size interval and likewise for a smaller sample size.

(i) As we increase the confidence level, we need to increase the sample size or the error bound, according to the error bound calculation, 206people in the firm must be polled.

Step by step solution

01

Explanation (a)

i. The average weight of the 16bags of2ounce candy in the sample, x¯=2

ii. The standard deviation of candy bag weights is 2ounces, σ=0.12

iii. The number of bags of candy that have been chosen is 16,n=16.

02

Explanation (b)

x is the weight of one candy bag.

03

Explanation (c)

The average weight of 16 bags of candy was calculated from a sample of 16 bags has mean weight isX¯.

04

Explanation (d)

The problem is solved using the normal distribution. As we know, the sample size is more than 30 for the population's standard deviation and the distribution of N2,0.1216

05

 Explanation (e)

i. The confidence interval should be stated.

The confidence interval's output,

by calculated through

n=15CI=(1.9589,2.0411)

ii. Below is a graph,

1.96 2.04

iii. The formula is used to compute the error bound.

EBM=Upperlimit-lower limit2

EBM=2.0411-1.95892

EBM=0.0411

06

Explanation (f)

1. The confidence interval should be stated.

By using calculator we get

n=16CI=(1.9418,2.0582)

2.The graph is as follows:

1.94 2.06

3. The formula is used to compute the error bound.

EBM=Upper limit-lower limit2

EBM=2.0582-1.94182

EBM=0.0582

07

Explanation (g)

The region defined by the normal curve is used to compute the confidence interval. If all of the limits remain the same, the level of confidence remains the same. The level of confidence associated with the area then rises.

08

Explanation (h)

We are 98% certain that the range 1.96to2.06 comprises the mean weight for actual pollution candies.

09

Explanation (i)

As we increase the confidence level, we need to increase the sample size or the error bound, according to the error bound calculation, 206people in the firm must be polled.

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Most popular questions from this chapter

Unoccupied seats on flights cause airlines to lose revenue. Suppose a large airline wants to estimate its mean number of unoccupied seats per flight over the past year. To accomplish this, the records of 225 flights are randomly selected and the number of unoccupied seats is noted for each of the sampled flights. The sample mean is 11.6 seats and the sample standard deviation is 4.1 seats.

a. i. x=__________

ii. sx=__________

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iv. n-1=__________

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Phone ModelSAR Phone ModelSAR
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Nokia E71x1.53
HTC Evo Design 4G0.8
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HTC Freestyle1.15
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Sagem Puma1.24
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Samsung Infuse 4G
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