Ch10 Review

All F tests are one-tailed tests.

FALSE

When the pooled-variance t test is inappropriate, the separate-variance t test for the difference between two independent means should be used.

TRUE

The t test for the difference between the means of two independent samples assumes that the respective:

all of the above.

A Pooled-Variance t Test for the Difference Between Two Independent Means may be used when

the two population variances are found not to besignificantly different

If we are testing for the difference between the means of two related samples with samples of n1 = 20 and n2= 20, the number of degrees of freedom is equal to:

19

When we test for differences between the means of two independent populations we can only use a two-tailed test.

FALSE

To investigate the efficacy of a diet, a random sample of 16 male patients is drawn from a population of adult male volunteers is collected. The weight of each individual in the sample is taken at the start of the diet, and at a medical follow-up four weeks later. Assume that the population of differences in weight before versus after the diet follow a normal distribution. What would be the appropriate statistical test to conduct the hypothesis test?

Paired t test

Hypothesis testing provides a "confirmatory" approach to data analysis.

TRUE

In testing for differences between the means of two related populations (i.e., Matched-Pairs) where the variance of the differences is unknown, the degrees of freedom are:

n-1

When testing for the difference between two population variances with sample sizes of n1 = 8 and n2 = 10, the number of degrees of freedom are:

numerator d.f. = 7, denominator d.f. = 9

When the population standard deviations are unknown, both samples are less than 30, and the equal variances assumption cannot be met, which test statistic should be used to test the differences between two independent means

separate-variance t-test for the difference between two means

In testing for differences between the means of two independent populations the null hypothesis states that:

the difference between the two population means is not significantly different from zero.

When testing for differences between the means of two related populations, the null hypothesis states that:

the population mean difference is not significantly different from zero.

The hypothesis test for the equality of two population variances is based on:

the ratio of the two sample variances.

If we are testing for the difference between the means of two independent samples with samples of n1 = 20 and n2= 20, the number of degrees of freedom is equal to:

38

The F test for the equality of two population variances is based on the difference between the two variances.

FALSE

The distribution of the F test statistic is symmetrical.

FALSE

When repeated measurements are taken from the same cases, the t test for independent means should be used.

FALSE

When sample sizes are small, the pooled-variance t test is robust with respect to moderate violations of the assumption of normality.

FALSE

To investigate the efficacy of a diet, a random sample of 16 male patients is drawn from a population of adult male volunteers is collected. The weight of each individual in the sample is taken at the start of the diet, and at a medical follow-up four weeks later. Assume that the population of differences in weight before versus after the diet follow a normal distribution. If it is hypothesized that the diet will lead to a statistically significant loss in weight, what type of hypothesis test should be conducted?

one

In testing for the differences between the means of two independent populations where the variances in each population are unknown but assumed equal, the degrees of freedom are:

n1 + n2 - 2

Repeated measurements from the same individuals is an example of data collected from two related populations.

TRUE

The test for the difference of two independent population means assumes that each of the two populations is normally distributed.

TRUE

When testing the null hypothesis using the confidence interval estimate of the difference between two means, one would reject the null hypothesis when

the confidence interval does not include zero