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### A statistical hypothesis is a claim or a statement either about the value of a single population characteristic or about the values of several population characteristics.

True

### The null hypothesis is only rejected in favor of the alternative hypothesis when there is convincing evidence against the null hypothesis.

True

### If the null hypothesis is not rejected, then there is strong statistical evidence that the null hypothesis is true.

False

### Every reasonable test comes with a guarantee that neither a type I nor a type II error will be made.

False

### The fundamental idea behind hypothesis testing is to reject H o only when the observed sample is very unlikely to have occurred when H o is true.

True

### In a large sample z test for mu, the calculated value of z is the absolute distance between x bar and the true value of mu.

False

### The null hypothesis should be rejected when the p-value is larger than the significance level of the test.

False

### It is customary to say that the result of a hypothesis test is statistically significant when the p-value is smaller than alpha.

True

### In a large sample z test for p hat, the calculated value of z expresses the distance between p and the hypothesized value as a number of standard deviations.

True

### The central limit theorem provides the justification for both the large sample z test and the small sample t test for mu.

False

### For testing H o: mu=50 versus H a: mu<50, a calculated z value of -1.98 will have a smaller p-value than would a calculated z value of -1.80.

True

### For a two-tailed t test, the p-value for a calculated t value of 2.37 is twice the area to the right of 2.37 on the t curve.

True

### The small sample t test for mu should only be used when the population being sampled is approximately normal.

True

### When H o is not rejected and beta is large, then there is strong evidence that H o is actually true.

False

### Two samples are said to be independent when the selection of the individuals or objects in one sample has no bearing on the selection of those in the other sample.

True

### The variance of a difference of two independent quantities is the sum of their individual variances.

True

### When the assignment of treatments used in a comparison of treatments is made by the investigators the study is said to observational.

False

### In an experiment involving two treatments, rejection of H o: mu1-mu2=0 in favor of H a: mu1-mu2<0 suggests that treatment 2 associates with higher values of the variable to occur.

False

### The estimated standard deviation of xbar1-xbar2 used in both the large sample and small sample confidence intervals for mu1-mu2 are the same.

True

### The large sample z test for mu1-mu2 can be used as long as at least one of the two sample sizes, n1 and n2, is greater than 30.

False

### The degrees of freedom of the two-sample t test statistic are based entirely on the values of the sample standard deviations and the sample sizes.

True

### The p-value of an upper-tail t test is the area to the right of the calculated t value on the t curve.

True

### The degrees of freedom of the two-sample t test statistic are the same as the degrees of freedom for the paired t test statistic.

False

### The degrees of freedom used in the two-sample t test are the same as the degrees of freedom used in the two-sample t confidence interval for mu1-mu2.

True

### The standard deviation of p1-p2 used in the large sample test of phat1-phat2 is the same as the standard deviation of p1-p2 used in the large sample confidence interval for phat1-phat2.

False

### The test statistic for the rank sum test of mu1-mu2 is the difference of the ranks of the first and second samples.

False