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2021-05-05
Answered

What is meant by the term “90% confident” when constructing a confidence interval for a mean? a. If we took repeated samples, approximately 90% of the samples would produce the same confidence interval. b. If we took repeated samples, approximately 90% of the confidence intervals calculated from those samples would contain the sample mean. c. If we took repeated samples, approximately 90% of the confidence intervals calculated from those samples would contain the true value of the population mean. d. If we took repeated samples, the sample mean would equal the population mean in approximately 90% of the samples.

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Maciej Morrow

Answered 2021-05-06
Author has **98** answers

By the term 90% confident” we mean that:

c) if we took repeated samples, approximately 90% of the confidence intervals calculated from those samples would contain the true value of the population mean.

d) if we took repentedsamples, the sample mean would equal the population mean in approximately 90% of the samples.

c) if we took repeated samples, approximately 90% of the confidence intervals calculated from those samples would contain the true value of the population mean.

d) if we took repentedsamples, the sample mean would equal the population mean in approximately 90% of the samples.

asked 2021-03-09

In a study of the accuracy of fast food drive-through orders, Restaurant A had 298 accurate orders and 51 that were not accurate. a. Construct a 90% confidence interval estimate of the percentage of orders that are not accurate. b. Compare the results from part (a) to this 90% confidence interval for the percentage of orders that are not accurate at Restaurant B:

asked 2021-02-23

Suppose that a random sample of 50 bottles of a particular brand of cough syrup is selected and the alcohol content of each bottle is determined. Let j: denote the average alcohol content for the population of all bottles of the brand under study. Suppose that the resulting 95% confidence intervals (7-8, 9.6)

(a) Would 2 90%% confidence interval calculated from this same sample have been narrower or wider than the glven interval? Explain your reasoning.

(b) Consider the following statement: There is 9 95% chance that Is between 7.8 and 9.6. Is this statement correct? Why or why not?

(c) Consider the following statement: We can be highly confident that 95% of al bottles ofthis type of cough syrup have an alcohol content that is between 7.8 and 9.6. Is this statement correct? Why or why not?

(a) Would 2 90%% confidence interval calculated from this same sample have been narrower or wider than the glven interval? Explain your reasoning.

(b) Consider the following statement: There is 9 95% chance that Is between 7.8 and 9.6. Is this statement correct? Why or why not?

(c) Consider the following statement: We can be highly confident that 95% of al bottles ofthis type of cough syrup have an alcohol content that is between 7.8 and 9.6. Is this statement correct? Why or why not?

asked 2021-08-04

A random sample of 100 automobile owners in the state of Virginia shows that an automobile is driven on average 23,500 kilometers per year with a standard deviation of 3900 kilometers.

Assume the distribution of measurements to be approximately normal.

a) Construct a$99\mathrm{\%}$ confidence interval for the average number of kilometers an automobile is driven annually in Virginia.

b) What can we assert with$99\mathrm{\%}$ confidence about the possible size of our error if we estimate the average number of kilometers driven by car owners in Virginia to be 23,500 kilometers per year?

Assume the distribution of measurements to be approximately normal.

a) Construct a

b) What can we assert with

asked 2021-08-03

A simple random sample of 60 items resulted in a sample mean of 80. The population standard deviation is $\sigma =15$

a) Compute the$95\mathrm{\%}$ confidence interval for the population mean. Round your answers to one decimal place.

b) Assume that the same sample mean was obtained from a sample of 120 items. Provide a$95\mathrm{\%}$ confidence interval for the population mean. Round your answers to two decimal places.

c) What is the effect of a larger sample size on the interval estimate?

Larger sample provides a-Select your answer-largersmallerItem 5 margin of error.

a) Compute the

b) Assume that the same sample mean was obtained from a sample of 120 items. Provide a

c) What is the effect of a larger sample size on the interval estimate?

Larger sample provides a-Select your answer-largersmallerItem 5 margin of error.

asked 2021-07-31

The number of rescue calls received by a rescue squad in a city follows a Poisson distribution with 2.83 per day. The squad can handle at most four calls a day.

a. What is the probability that the squad will be able to handle all the calls on a particular day?

b. The squad wants to have at least$95\mathrm{\%}$ confidence of being able to handle all the calls received in a day. At least how many calls a day should the squad be prepared for?

c. Assuming that the squad can handle at most four calls a day, what is the largest value of that would yield$95\mathrm{\%}$ confidence that the squad can handle all calls?

a. What is the probability that the squad will be able to handle all the calls on a particular day?

b. The squad wants to have at least

c. Assuming that the squad can handle at most four calls a day, what is the largest value of that would yield

asked 2022-03-26

Confidence interval and standard deviation

I'm currently talking an intermediate course in finance where we want to calculate Value-at-Risk for portfolios and bonds. To use this VaR formula I need to know the standard deviation for different confidence intervals. Now my teacher have put up the following standard deviation for different confidence intervals:

$C.I90=\frac{+}{-}1,64S.d$

$C.I95=\frac{+}{-}1,96S.d$

$C.I98=\frac{+}{-}2,33S.d$

$C.I99,9=\frac{+}{-}3,09S.d$

When I watched an old exam for calculating VaR, the C.I was 99% and the student wrote that the S.d was equal to 2,33. How is this possible? (P:s the student got an A on this exam).

I'm currently talking an intermediate course in finance where we want to calculate Value-at-Risk for portfolios and bonds. To use this VaR formula I need to know the standard deviation for different confidence intervals. Now my teacher have put up the following standard deviation for different confidence intervals:

When I watched an old exam for calculating VaR, the C.I was 99% and the student wrote that the S.d was equal to 2,33. How is this possible? (P:s the student got an A on this exam).

asked 2021-06-01

Suppose that you take 500 simple random samples from a population and that, for each sample, you obtain a 90% confidence interval for an unknown parameter. Approximately how many of those confidence intervals will not contain the value of the unknown parameter?