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