Statistics -146

A 90% confidence interval for the mean percentage of airline reservations being canceled on the day of the flight is (1.2%, 4.5%). What is the point estimator of the mean percentage of reservations that are canceled on the day of the flight?

2.85%

A 95% confidence interval indicates that:

95% of the time, intervals constructed using this process based on all possible samples of the same size from this population will include the population mmean..

Suppose a 95% confidence interval for μ turns out to be (130, 300). To make more useful inferences from the data, it is desired to reduce the width of the confidence interval. Which of the following will result in a reduced interval width?

All of these. <Increase the sample size. Decrease the confidence level. Increase the sample size and decrease the confidence level.>

Three years ago, the mean price of a single-family home was $243,786. A real estate broker believes that the true mean price of single family homes has decreased since then. Suppose the null hypothesis is NOT rejected. State the conclusion based on the results of the test.

At the 5% level of significance we cannot conclude that the true mean price of a single-family home has decreased.

What is the H0 for testing differences of the means of two independent samples?

H0:μ1 - μ2 = 0

Which of the following is NOT one of the forms possible for an alternative hypothesis?

Ha: population parameter = hypothesized value

In a hypothesis test involving a population mean, which of the following would be an acceptable form of the null and alternative hypothesis?

Ho : µ = $1,700 Ha : µ > $1,700

Suppose a 90% confidence interval for μ turns out to be (120, 280). Based on the interval, do you believe the average is equal to 300?

No, and I am 90% sure of it.

Which of the following is correct with regards to hypothesis testing?

The researcher always begins by assuming the null hypothesis H0 is true.

To test whether Thrifty Car Rental is less expensive than Hertz, a researcher collected data from 10 different cities on the daily rental rate for a compact car charged by Hertz and by Thrifty. What statistical procedure will the researcher use to analyze the data?

Two sample t-test, Independent samples.

A physical therapist wanted to know whether, after exercise, the mean pulse of men was less than the mean pulse of women. She randomly selected 50 men and 50 women to participate in the study. Each subject was required to step up and down a 6-inch platform and the pulse of each subject was recorded. What statistical procedure should be used here (all assumptions necessary for statistical inference have been satisfied)?

Two-sample means test, independent samples.

When conducting a formal hypothesis test there are different errors that may be made, depending on your decision. What type of error has been committed if you fail to reject a null hypothesis that is actually false?

Type 2 Error

Classify the two given samples as independent or dependent. Sample 1: Pre-training blood pressure of 27 people Sample 2: Post-training blood pressure of 27 people

dependent

A ______________ is a statement or claim regarding a characteristic of one or more populations.

hypothesis

Classify the two given samples as independent or dependent. Sample 1: The heights in inches of 19 newborn females Sample 2: The heights in inches of 19 newborn males

independent

Classify the two given samples as independent or dependent. Sample 1: The scores of 23 students who took a statistics final Sample 2: The scores of 23 different students who took a physics final

independent

If the individuals selected for a sample have no influence upon which individuals are selected for a second sample, then the samples are said to be

independent

When forming a confidence interval for matched-pair data the point estimate is the

mean of the differences.

The ______________ hypothesis contains the "=" sign.

null

The p-value is the

observed significance level of a hypothesis test

When performing a hypothesis test upon two dependent samples, the variable of interest is

the differences that exist between the matched-pair data.

Two samples are said to be dependent if

the individuals in one sample are used to determine the individuals in a second sample.

To determine whether the normal probability plot indicates that the sample data could have come form a population that is normally distributed,

we look for a plot that is approximately linear, and an A.D. p-value which is greater than 0.05 so the population from which the sample was drawn is probably normally distributed.

A hypothesis test is a "two-tailed" if the alternative hypothesis contains a _______ sign.

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