1.In a random sample of 81 audited estate taxreturns, it was determined that the mean amount of additional tax owed was $3416 with a standard deviation of $2559. Construct and interpret a90% confidence interval for the mean additional amount of tax owed for estate tax returns.

Find and interpret a90% confidence interval for the mean additional amount of tax owed for estate tax returns. Select the correct choice below and fill in the answer boxes to complete your choice.

(Use ascending order. Round to the nearest dollar asneeded.)

A.

90% of taxes owed for estate tax returns are between $

nothing

and $

nothing

.

B.

There is a90% probability that the mean additional tax owed is between $

nothing

and $

nothing

.

C.

One can be90% confident that the mean additional tax owed is between $

nothing

and $

nothing

.

2.Sleep apnea is a disorder in which you have one or more pauses in breathing or shallow breaths while you sleep. In across-sectional study of 420 adults who suffer from sleepapnea, it was found that 294 had gum disease.Note: In the generalpopulation, about17.5% of individuals have gum disease. Complete parts(a) through(c) below.

Click here to view the standard normal distribution table (page 1).LOADING...

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(a) What does it mean for this study to becross-sectional?

A.

The data were obtained at a specific point in time and the study was an observational study.

B.

The data were obtained over the course of time and the study was an observational study.

C.

The data were obtained at a specific point in time and the study was an experiment.

D.

The data were obtained over the course of time and the study was an experiment.

(b) What is the variable of interest in thisstudy? Is it qualitative orquantitative? Explain. Identify the variable of interest. Choose the correct answer below.

A.

Whether a person has gum disease or not.

B.

The proportion of gum disease present in those with sleep apnea.

C.

Whether a person has sleep apnea or not.

D.

Whether a person with sleep apnea has gum disease or not.

Determine whether the variable in question is qualitative or quantitative. Choose the correct answer below.

A.

Qualitativethe variable classifies the individuals in the study.

B.

Quantitativethe variable classifies the individuals in the study.

C.

Qualitativethe variable can be numerically measured.

D.

Quantitativethe variable can be numerically measured.

(c) Estimate the proportion of individuals who suffer from sleep apnea who have gum disease with 90% confidence. Interpret your result. Select the correct choice below and fill in the answer boxes to complete your choice.

(Use ascending order. Round to three decimal places asneeded.)

A.

There is a 90% chance that the true population proportion of individuals who suffer from sleep apnea who have gum disease is between

nothing

and

nothing

.

B.

There is 90% confidence that the population proportion of individuals who suffer from sleep apnea who have gum disease is between

nothing

and

nothing

.

C.

90% of the population lies in the interval between

nothing

and

nothing

.