The volumes (in ounces) of juice in eight randomly selected juice bottles are as follows: $\begin{array} { l l l l } 15.7 & 15.0 & 15.1 & 15.8 \\ 15.4 & 15.2 & 15.5 & 15.6 \end{array}$ Find a 99% confidence interval for the standard deviation, $\sigma$ , of the volumes of juice in all such bottles. Round to the nearest hundredth when necessary.

A) (0.19, 0.88) B) (0.17, 0.66) C) (0.17, 0.77) D) (0.16, 0.66) A) (0.19, 0.88) B) (0.17, 0.66) C) (0.17, 0.77) D) (0.16, 0.66)

Exam 6: Inferences Based on a Single Sample: Estimation With Confidence Intervals

The U.S. Commission on Crime randomly selects 600 files of recently committed crimes in an area and finds 380 in which a firearm was reportedly used. Find a 99% confidence interval for p, the true fraction of crimes in the area in which some type of firearm was reportedly used.

(Essay)

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Question 61

What is the confidence level of the following confidence interval for $\mu$ ? $\bar { x } \pm 2.33 \left( \frac { \sigma } { \sqrt { n } } \right)$

(Multiple Choice)

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Question 62

A random sample of n measurements was selected from a population with unknown mean µ and known standard deviation ?. Calculate a 95% confidence interval for µ for the given situation. Round to the nearest hundredth when necessary. $\mathrm { n } = 100 , \overline { \mathrm { x } } = 74 , \sigma = 25$

(Multiple Choice)

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Question 63

A university dean is interested in determining the proportion of students who receive some sort of financial aid. Rather than examine the records for all students, the dean randomly selects 200 students and finds that 118 of them are receiving financial aid. Use a 95% confidence interval to estimate the true proportion of students who receive financial aid.

(Multiple Choice)

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Question 64

If no estimate of p exists when determining the sample size for a confidence interval for a proportion, we can use .5 in the formula to get a value for n.

(True/False)

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Question 65

For $n = 40 \text { and }\hat { p} = .45 \text {, }$ s the sample size large enough to construct a confidence for p?

(Essay)

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Question 66

A local men's clothing store is being sold. The buyers are trying to estimate the percentage of items that are outdated. They will choose a random sample from the 100,000 items in the store's inventory in order to determine the proportion of merchandise that is outdated. The current owners have never determined the percentage of outdated merchandise and cannot help the buyers. How large a sample do the buyers need in order to be 95% confident that the margin of error of their estimate is about 5%?

(Multiple Choice)

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Question 67

Suppose you want to estimate a population proportion $p$ where $\hat { p } = 0.61 , n = 1000$ , and $N = 7500$ . Find an approximate $95 \%$ confidence interval for p.

(Multiple Choice)

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Question 68

A marketing research company is estimating which of two soft drinks college students prefer. A random sample of 329 college students produced the following 95% confidence interval for the proportion of college students who prefer one of the colas: (.329, .474). What additional assumptions are necessary for the interval to be valid?

(Multiple Choice)

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Question 69

The volumes (in ounces) of juice in eight randomly selected juice bottles are as follows: 15.7 15.0 15.1 15.8 15.4 15.2 15.5 15.6 Find a 99% confidence interval for the standard deviation, $\sigma$ , of the volumes of juice in all such bottles. Round to the nearest hundredth when necessary.

(Multiple Choice)

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Question 70

What type of car is more popular among college students, American or foreign? One hundred fifty-nine college students were randomly sampled and each was asked which type of car he or she prefers. A computer package was used to generate the printout below of a 90% confidence intervaln for the proportion of college students who prefer American automobiles. SAMPLE PROPORTION $= .396$ $\text { SAMPLE SIZE = } 159$ UPPER LIMIT $= .460$ LOWER LIMIT $= .332$ Based on the interval above, do you believe that 31% of all college students prefer American automobiles?

(Multiple Choice)

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Question 71

Suppose a large labor union wishes to estimate the mean number of hours per month a union member is absent from work. The union decides to sample 468 of its members at random and monitor the working time of each of them for 1 month. At the end of the month, the total number of hours absent from work is recorded for each employee. Which of the following should be used to estimate the parameter of interest for this problem?

(Multiple Choice)

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Question 72

Calculate the percentage of the population sampled if n = 250 and N = 1000. Should the standard error in this situation be multiplied by a finite population correction factor? Explain.

(Essay)

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Question 73

Sales of a new line of athletic footwear are crucial to the success of a newly formed company. The company wishes to estimate the average weekly sales of the new footwear to within $150 with 90% reliability. The initial sales indicate that the standard deviation of the weekly sales figures is approximately $1500. How many weeks of data must be sampled for the company to get the information it desires?

(Essay)

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Question 74

The confidence level is the confidence coefficient expressed as a percentage.

(True/False)

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Question 75

A computer package was used to generate the following printout for estimating the mean sale price of homes in a particular neighborhood. $X =$ sale_price SAMPLE MEAN OF $X = \quad 46,400$ SAMPLE STANDARD DEV $= 13,747$ SAMPLE SIZE OF X $= \quad 15$ CONFIDENCE $= \quad 90$ UPPER LIMIT $= 52,650.6$ SAMPLE MEAN OF X $= \quad 46,400$ LOWER LIMIT $= 40,149.4$ Which of the following is a practical interpretation of the interval above?

(Multiple Choice)

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Question 76

For data with two outcomes (success or failure), the binomial proportion of successes is likely to be the parameter of interest.

(True/False)

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Question 77

Parking at a large university can be extremely difficult at times. One particular university is trying to determine the location of a new parking garage. As part of their research, officials are interested in estimating the average parking time of students from within the various colleges on campus. A survey of 338 College of Business (COBA) students yields the following descriptive information regarding the length of time (in minutes) it took them to find a parking spot. Note that the "Lo 95%" and "Up 95%" refer to the endpoints of the desired confidence interval. Variable N Lo 95\% CI Mean Up 95\% CI SD Parking Time 338 9.1944 10.466 11.738 11.885 Explain what the phrase "95% confident" means when working with a 95% confidence interval.

(Multiple Choice)

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Question 78

A university dean is interested in determining the proportion of students who receive some sort of financial aid. Rather than examine the records for all students, the dean randomly selects 200 students and finds that 118 of them are receiving financial aid. If the dean wanted to estimate the proportion of all students receiving financial aid to within 1% with 90% reliability, how many Students would need to be sampled?

(Multiple Choice)

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Question 79

Suppose a large labor union wishes to estimate the mean number of hours per month a union member is absent from work. The union decides to sample 348 of its members at random and monitor the working time of each of them for 1 month. At the end of the month, the total number of hours absent from work is recorded for each employee. If the mean and standard deviation of the sample are $\bar { x } = 7.5$ hours and $s = 3.5$ hours, find a $99 \%$ confidence interval for the true mean number of hours a union member is absent per month. Round to the nearest thousandth.

(Multiple Choice)

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Question 80

Showing 61 - 80 of 135

The U.S. Commission on Crime randomly selects 600 files of recently committed crimes in an area and finds 380 in which a firearm was reportedly used. Find a 99% confidence interval for p, the true fraction of crimes in the area in which some type of firearm was reportedly used.

What is the confidence level of the following confidence interval for $\mu$ ? $\bar { x } \pm 2.33 \left( \frac { \sigma } { \sqrt { n } } \right)$

If no estimate of p exists when determining the sample size for a confidence interval for a proportion, we can use .5 in the formula to get a value for n.

For $n = 40 \text { and }\hat { p} = .45 \text {, }$ s the sample size large enough to construct a confidence for p?

Suppose you want to estimate a population proportion $p$ where $\hat { p } = 0.61 , n = 1000$ , and $N = 7500$ . Find an approximate $95 \%$ confidence interval for p.

The volumes (in ounces) of juice in eight randomly selected juice bottles are as follows: 15.7 15.0 15.1 15.8 15.4 15.2 15.5 15.6 Find a 99% confidence interval for the standard deviation, $\sigma$ , of the volumes of juice in all such bottles. Round to the nearest hundredth when necessary.

Calculate the percentage of the population sampled if n = 250 and N = 1000. Should the standard error in this situation be multiplied by a finite population correction factor? Explain.

The confidence level is the confidence coefficient expressed as a percentage.

For data with two outcomes (success or failure), the binomial proportion of successes is likely to be the parameter of interest.

Statistics, Data, and Statistical Thinking

Methods for Describing Sets of Data

Probability

Random Variables and Probability Distributions

Sampling Distributions

Inferences Based on a Single Sample: 355 Tests of Hypotheses

Inferences Based on Two Samples: Confidence Intervals and Tests of Hypotheses

Design of Experiments and Analysis of Variance

Categorical Data Analysis

Simple Linear Regression

Multiple Regression and Model Building

Methods for Quality Improvement: Statistical Process Control Available on CD

Time Series: Descriptive Analyses, Models, and Forecasting Available on CD

Nonparametric Statistics Available on CD

Filters

Exam 6: Inferences Based on a Single Sample: Estimation With Confidence Intervals

The U.S. Commission on Crime randomly selects 600 files of recently committed crimes in an area and finds 380 in which a firearm was reportedly used. Find a 99% confidence interval for p, the true fraction of crimes in the area in which some type of firearm was reportedly used.

What is the confidence level of the following confidence interval for μ\muμ ? xˉ±2.33(σn)\bar { x } \pm 2.33 \left( \frac { \sigma } { \sqrt { n } } \right)xˉ±2.33(n​σ​)

If no estimate of p exists when determining the sample size for a confidence interval for a proportion, we can use .5 in the formula to get a value for n.

For n=40 and p^=.45, n = 40 \text { and }\hat { p} = .45 \text {, }n=40 and p^​=.45, s the sample size large enough to construct a confidence for p?

Suppose you want to estimate a population proportion ppp where p^=0.61,n=1000\hat { p } = 0.61 , n = 1000p^​=0.61,n=1000 , and N=7500N = 7500N=7500 . Find an approximate 95%95 \%95% confidence interval for p.

The volumes (in ounces) of juice in eight randomly selected juice bottles are as follows: 15.7 15.0 15.1 15.8 15.4 15.2 15.5 15.6 Find a 99% confidence interval for the standard deviation, σ\sigmaσ , of the volumes of juice in all such bottles. Round to the nearest hundredth when necessary.

Calculate the percentage of the population sampled if n = 250 and N = 1000. Should the standard error in this situation be multiplied by a finite population correction factor? Explain.

The confidence level is the confidence coefficient expressed as a percentage.

For data with two outcomes (success or failure), the binomial proportion of successes is likely to be the parameter of interest.

Statistics, Data, and Statistical Thinking

Methods for Describing Sets of Data

Probability

Random Variables and Probability Distributions

Sampling Distributions

Inferences Based on a Single Sample: 355 Tests of Hypotheses

Inferences Based on Two Samples: Confidence Intervals and Tests of Hypotheses

Design of Experiments and Analysis of Variance

Categorical Data Analysis

Simple Linear Regression

Multiple Regression and Model Building

Methods for Quality Improvement: Statistical Process Control Available on CD

Time Series: Descriptive Analyses, Models, and Forecasting Available on CD

Nonparametric Statistics Available on CD

Filters

What is the confidence level of the following confidence interval for $\mu$ ? $\bar { x } \pm 2.33 \left( \frac { \sigma } { \sqrt { n } } \right)$

For $n = 40 \text { and }\hat { p} = .45 \text {, }$ s the sample size large enough to construct a confidence for p?

Suppose you want to estimate a population proportion $p$ where $\hat { p } = 0.61 , n = 1000$ , and $N = 7500$ . Find an approximate $95 \%$ confidence interval for p.

The volumes (in ounces) of juice in eight randomly selected juice bottles are as follows: 15.7 15.0 15.1 15.8 15.4 15.2 15.5 15.6 Find a 99% confidence interval for the standard deviation, $\sigma$ , of the volumes of juice in all such bottles. Round to the nearest hundredth when necessary.