BSTAT 2

The t value with a 95% confidence and 24 degrees of freedom is

2.064

The z value for a 97.8% confidence interval estimation is

2.29

A sample of size 350 selected from one population has 325 successes, and a sample of size 225 selected from a second population has 193 successes. The test statistic for testing the equality of the population proportions equal to

2.77

The number of degrees of freedom associated with the t test, when the data are gathered from a matched pairs experiment with 30 pairs, is:

29

It is known that the population variance equals 484. With a 0.95 probability, the sample size that needs to be taken to estimate the population mean if the desired margin of error is 5 or less is

75

A sample of 26 elements from a normally distributed population is selected. The sample mean is 10 with a standard deviation of 4. The 95% confidence interval for the population mean is

8.384 to 11.616

In hypothesis testing, the critical value is:

A number that establishes the boundary of the rejection region

If a hypothesis is not rejected at a 6% significance level, it will

Also not be rejected at the 3% level

The average life expectancy of tires produced by the Whitney Tire Company has been 40,000 miles. Management believes that due to a new production process, the life expectancy of its tires has increased. In order to test the validity of this belief, the correct set of hypotheses is

H0: m £ 40,000 Ha: m > 40,000x

A one-tailed test is a

Hypothesis test in which rejection region is one tail of the sampling distribution

A random sample of 25 employees of a local company has been measured. A 95% confidence interval estimate for the mean systolic blood pressure for all company employees is 123 to 139. Which of the following statements is valid?

If the sampling procedure were repeated many times, 95% of the resulting confidence intervals would contain the population mean systolic blood pressure.

Excel's ___ function can be used to calculate a p-value for a hypothesis test

NORMSDIST

Excel's __________ function can be used to calculate a p-value for a hypothesis test.

NORMSDIST

A meteorologist stated that the average temperature during July in Chattanooga was 80 degrees. A sample of 32 Julys was taken. The correct set of hypotheses is

None of the other answers are correct.

Which of the following does not need to be known in order to compute the p-value?

The level of significance

The probability of making a Type I error is denoted by

a

The error of rejecting a true null hypothesis is

a Type I error

In hypothesis testing, the critical value is

a number that establishes the boundary of the rejection region

The probability of making a Type I error is denoted by:

alpha

If a hypothesis is not rejected at a 5% level of significance, it will

also not be rejected at the 1% level

If we are interested in testing whether the mean of population A is at least as big as the mean of population B, the:

alternative hypothesis should state: µA - µB < 0

As the number of degrees of freedom for a t distribution increases, the difference between the t distribution and the standard normal distribution

becomes smaller

When the level of confidence increases, the confidence interval

becomes wider

As the sample size increases, the margin of error

decreases

Whenever using the t distribution in interval estimation, we must assume that the

degrees of freedom equals n - 1

A two-tailed test is a

hypothesis test in which rejection region is in both tails of the sampling distribution

The level of significance is the

maximum allowable probability of Type I error

A p-value is the

probability, when the null hypothesis is true, of obtaining a sample result that is at least as unlikely as what is observed

In point estimation, data from the

sample is used to estimate the population parameter

The absolute value of the difference between the point estimate and the population parameter it estimates is the

sampling error

From a population that is normally distributed with an unknown standard deviation, a sample of 25 elements is selected. For the interval estimation of the population mean, the proper distribution to use is the

t distribution with 24 degrees of freedom

The symbol XbarD refers to:

the mean difference in the pairs of observations taken from two dependent samples

In determining the sample size necessary to estimate a population proportion, which of the following information is not needed?

the mean of the population

In general, higher confidence levels provide

wider confidence intervals