Exam 10: A: Inference From Small Samples

On which of the following does the shape of the chi-square distribution depend?

For a sample of size 20 taken from a normally distributed population with standard deviation equal to 5, which of the following would be required to construct a 90% confidence interval for the population mean?

A two-tailed test for two population variances could have the null hypothesis written as

Researchers determined that 60 tissues is the average number of tissues used during a cold. Suppose a random sample of 100 tissue users yielded the following data on the number of tissues used during a cold: = 52 and s = 22. Suppose the alternative we wanted to test is . Which of the following best describes the rejection region for = 0.05?

You wish to test the difference between the means of two paired populations with samples of size 30 each. What is the appropriate value of the degrees of freedom for this test?

If a sample has 15 observations and a 95% confidence estimate for needs to be constructed, the appropriate t score is 2.131.

In what type of test is the variable of interest the difference between the values of the observations rather than the observations themselves?

Which of the following is an assumption behind the paired-difference t test for the mean difference between two populations?

When finding a confidence interval for a population mean based on a sample of size 8, which of the following assumptions is made?

You are testing vs. using a sample of 15 observations and a significance level equal to 0.05. What is the critical value of the test?

Which of these statements could be used to describe the chi-square distribution?

To estimate with 95% confidence the average number of kilometres that students living off-campus commute to classes every day, a random sample of 20 students was taken and produced a mean equal to 5.2 km and a standard deviation of 3.05 km. Under these circumstances, what is the appropriate critical value?

In making inferences about a population mean , the degrees of freedom used in t distribution are equal to the sample size.

Two independent samples of sizes 20 and 30 are randomly selected from two normally distributed populations in order to test the difference between the population means, . Assume that the population variances are unknown but equal. From the following options, how may the sampling distribution of the sample mean difference best be described?

In testing vs. the F-test statistic is calculated as F = , where are the two sample variances and is the smaller of the two.

The t distribution allows the calculation of confidence intervals for means when the actual standard error is not known.

The F distribution is used in testing the hypotheses vs.

What do the values in a t distribution table measure?

A random sample of size 20 taken from a normally distributed population resulted in a sample variance of 32. What would be the lower limit of a 90% confidence interval for the population variance?

In testing for differences between the means of two dependent populations, which of the following is the best formulation of the null hypothesis?