Stats 153
b. Can the F test statistic ever be a negative number?
No, because sample variances cannot be negative, and the result of dividing the squares of two nonnegative numbers is never negative.
Which of the following is NOT true when using one-way analysis of variance for testing equality of three or more population means? Choose the correct answer below. A. Small F test statistics indicate that the decision is to reject the null hypothesis of equal means. B. Small P-values indicate that the decision is to reject the null hypothesis of equal means. C. The conclusion that there is sufficient evidence to reject the claim of equal population means does not indicate a particular mean is different from the others. D. The numerator of the F test statistic measures variation between sample means.
A
Which of the following is not true when using the confidence interval method for testing a claim about mu when sigma is unknown? Choose the correct answer below. A. The P-value method and the classical method are not equivalent to the confidence interval method in that they may yield different results. B. For a one-tailed hypothesis test with a 0.05 significance level, one must construct a 90% confidence interval. C. The P-value method, the traditional method, and the confidence interval method are equivalent and yield the same results. D. For a two-tailed hypothesis test with a 0.05 significance level, one must construct a 95% confidence interval.
A
Which of the following is NOT true of confidence interval estimates of the difference between two population proportions? Choose the correct answer below. A. A confidence interval is used to test a claim about two population proportions. B. The confidence interval uses a standard deviation based on estimated values of the population proportions. C. A confidence interval is used to estimate the difference between two population proportions. D. If a confidence interval estimate of p 1minusp 2 does not include 0, we have evidence suggesting that p 1 and p 2 have different values.
A
Which of the following is NOT a criterion for making a decision in a hypothesis test? Choose the correct answer below. A. If P-valueless than or equalsalpha, the decision is to reject the null hypothesis. Otherwise, we fail to reject the null hypothesis. B. If the P-value is less than 0.05, the decision is to reject the null hypothesis. Otherwise, we fail to reject the null hypothesis. .C. If the test statistic falls within the critical region, the decision is to reject the null hypothesis. D. If a confidence interval does not include a claimed value of a population parameter, the decision is to reject the null hypothesis.
B
Which of the following is NOT a reason why the procedures to estimate differences of two proportions or testing a claim about two proportions work? Choose the correct answer below. A. The variance of the differences between two independent random variables is the sum of their individual variances. B. The form of the confidence interval utilizes the same variance as when testing claims using hypothesis tests. C. The pooled estimate of the common value of p 1 and p 2 is p overbarequalsStartFraction x 1 plus x 2 Over n 1 plus n 2 EndFraction . D. Since ModifyingAbove p with caret 1 and ModifyingAbove p with caret 2 are each approximated by a normal distribution, the difference ModifyingAbove p with caret 1minusModifyingAbove p with caret 2 will also be approximated by a normal distribution with mean p 1minusp 2.
B
Which of the following is NOT a requirement for testing a claim about two population standard deviations or variances? Choose the correct answer below. A. This test requires that both populations have normal distributions. B. One of the populations is normally distributed. C. The two samples are simple random samples. D. The populations are independent.
B
Which of the following is NOT a requirement of testing a claim about a population proportion using a formal method of hypothesis testing? Choose the correct answer below. A. The conditions for a binomial distribution are satisfied. B. The lowercase symbol, p, represents the probability of getting a test statistic at least as extreme as the one representing sample data and is needed to test the claim. C. The conditions npgreater than5 and nqgreater than5 are both satisfied. D. The sample observations are a simple random sample.
B
Which of the following is NOT true about P-values in hypothesis testing? Choose the correct answer below. A. If the P is high, the null will fly. B. The P-value separates the critical region from the values that do not lead to rejection of the null hypothesis. C. If the P is low, the null must go. D. The P-value is an area.
B
Which of the following is NOT true for a hypothesis test for correlation? Choose the correct answer below. A. If the P-value is less than or equal to the significance level, we should reject the null hypothesis and conclude that there is sufficient evidence to support the claim of a linear correlation. B. If |r|greater thancritical value, we should fail to reject the null hypothesis and conclude that there is not sufficient evidence to support the claim of a linear correlation. C. If the P-value is greater than the significance level, we should fail to reject the null hypothesis and conclude that there is not sufficient evidence to support the claim of a linear correlation. D. If |r|less than or equalscritical value, we should fail to reject the null hypothesis and conclude that there is not sufficient evidence to support the claim of a linear correlation.
B
Which of the following is NOT true of using the binomial probability distribution to test claims about a proportion? Choose the correct answer below. A. In a right-tailed test, the P-value is the probability of getting x or more successes among the n trials. B. One requirement of this method is that npgreater than5 and nqgreater than5. C. In a left-tailed test, the P-value is the probability of getting x or fewer successes among the n trials. D. This method uses the binomial probability distribution with the P-value method and uses the value of p assumed in the null hypothesis.
B
c. If testing the claim that sigma Subscript 1 Superscript 2 Baseline not equals sigma Subscript 2 Superscript 2, what do we know about the two samples if the test statistic is Fequals1? A. The two samples have fairly different standard deviations (or variances). B. The two samples have the same standard deviation (or variance). C. The two samples come from populations with the same standard deviation (or variance). D. The two samples have radically different standard deviations (or variances).
B
Which of the following is NOT true of the F test? Choose the correct answer below. A. The count five method is a relatively simple alternative to the F test, and it does not require normally distributed populations. B. All one-tailed F tests will be right-tailed. C. Small values of F are evidence against sigma Subscript 1 Superscript 2 Baseline equals sigma Subscript 2 Superscript 2.
C
Which of the following is NOT a requirement for testing a claim about a mean with sigma known? Choose the correct answer below. A. If the sample results (or more extreme results) can easily occur when the null hypothesis is true, we attribute the relatively small discrepancy between the assumption and the sample results to chance. B. A conclusion based on a confidence interval estimate will be the same as a conclusion based on a hypothesis test. C. If, under a given assumption, there is an exceptionally small probability of getting sample results at least as extreme as the results that were obtained, we conclude that the assumption is probably not correct. D. If the sample results (or more extreme results) cannot easily occur when the null hypothesis is true, we explain the discrepancy between the assumption and the sample results by concluding that the assumption is true, so we do not reject the assumption.
D
Which of the following is NOT a requirement for testing a claim about a population mean with sigma known? Choose the correct answer below. A. Either the population is normally distributed or ngreater than30 or both. B. The value of the population standard deviation is known. C. The sample is a simple random sample. D. The sample mean, x overbar is greater than 30.
D
Which of the following is NOT true of the F test statistic? Choose the correct answer below. A. FequalsStartFraction MS left parenthesis treatment right parenthesis Over MS left parenthesis error right parenthesis EndFraction , when testing with unequal sample sizes B. The F test statistic is never negative. C. FequalsStartFraction left parenthesis variance between samples right parenthesis Over left parenthesis variance with samples right parenthesis EndFraction D. If the F test statistic is large, then the P-value will be large.
D
Which of the following is NOT true of the F test? Choose the correct answer below. A. This test requires that both populations have normal distributions. B. This test uses the F distribution. C. This test compares two population variances or standard deviations. D. This test is very resistant to departures from normal distributions.
D
Which of the following is NOT true when dealing with independent samples? Choose the correct answer below. A. The confidence interval estimate of µ 1minusµ 2 is left parenthesis x overbar 1 minus x overbar 2 right parenthesis minus Upper E less than left parenthesis µ 1 minus µ 2 right parenthesis less than left parenthesis x overbar 1 minus x overbar 2 right parenthesis plus Upper E. B. When making an inference about the two means, the P-value and traditional methods of hypothesis testing result in the same conclusion as the confidence interval method. C. The null hypothesis µ 1equalsµ 2 or µ 1 minus µ 2 equals 0 can be tested using the P-value method, the traditional method, or by determining if the confidence interval limits for µ 1minusµ 2 contain 0. D. The variance of the differences between two independent random variables equals the variance of the first random variable minus the variance of the second random variable.
D
Which of the following is not a characteristic of the t test? Choose the correct answer below. A. The Student t distribution is different for different sample sizes. B. The Student t distribution has the same general bell shape as the standard normal distribution. C. The t test is robust against a departure from normality. D. The Student t distribution has a mean of tequals0 and a standard deviation of sequals1.
D
a. If s Subscript 1 Superscript 2 represents the larger of two sample variances, can the F test statistic ever be less than 1?
NO
The _________ of a hypothesis test is the probability (1 - beta) of rejecting a false null hypothesis.
POWER
The F distribution is:
Skewed Right
