Statistics Quiz 10 Questions

Question 1Attest is used in place of thezscore for groups when which of the following is not known?A.Sample meanB.Population meanC.Sample standard deviationD.Population standard deviation2.5 points Question 2Thetdistribution that you use to find your critical values closely resembles the normal distribution when:A.The sample mean is large.B.The sample variance is large.C.The sample size is large.D.The population standard deviation is large.2.5 points Question 3A researcher wishes to test the theory that men and women differ on a measure of personality. The researcher draws a sample of 35 men and a sample of 35 women. The sample means on the personality measure are men, 46.7; women, 51.4.Why cannot the researcher conclude, just by looking at the difference of 4.7 between the two sample means, that the difference between the population means isnot0?A.A difference less than 5 points is too small to draw conclusions.B.Sample sizes of 35 are too small to draw conclusions.C.Sampling error may have caused one or both samples to be unrepresentative of the corresponding populations.D.None of the above—the researcher should conclude that the difference between the population means is not 0.2.5 points Question 4A researcher wishes to test the theory that men and women differ on a measure of personality. The researcher draws a sample of 35 men and a sample of 35 women. The sample means on the personality measure are men, 46.7; women, 51.4.If the statistical analysis indicates that the null hypothesis should beretained, the researcher should conclude that:A.There is no statistically significant difference between men and women on this personality measure.B.There is a statistically significant difference between men and women on this personality measure.C.The population difference between men and women on this personality measure is 4.7 or more.D.None of the above2.5 points Question 5A researcher wishes to test the theory that men and women differ on a measure of personality. The researcher draws a sample of 35 men and a sample of 35 women. The sample means on the personality measure are men, 46.7; women, 51.4.If the statistical analysis indicates that the null hypothesis should berejected, the researcher should conclude that:A.Men and women are the same in the population on this personality measure.B.Men and women are not the same in the population on this personality measure.C.The population difference between men and women on this personality measure is 4.7 or more.D.None of the above2.5 points Question 6A researcher who obtains a statistically significant result for the difference between two means should usually conclude that:A.The result has practical importance.B.There is a strong relationship between membership in a population and scores on the variable being studied.C.The result should be supplemented by a measure of effect size.D.The researcher’s theory has been contradicted.2.5 points Question 7When testing hypotheses about the difference between the means of two populations, the degrees of freedom are:A.N1+N2B.N1–N2C.N1+N2– 1D.N1+N2– 22.5 points Question 8If we are testing a hypothesis about the difference between two population means and we switch from the .05 criterion of significance to the .01 criterion, what happens to the probabilities of a Type I error and a Type II error?A.Both probabilities become smaller.B.The probability of a Type I error becomes smaller, and the probability of a Type II error becomes larger.C.The probability of a Type I error becomes larger and the probability of a Type II error becomes smaller.D.Both probabilities become larger.2.5 points Question 9When using the two-groupttest with large samples, the results willnotbe accurate if:A.The dependent variable is not normally distributed within each population.B.The two sample variances differ substantially, and the sample sizes are far from being equal.C.Both of the aboveD.Neither of the above2.5 points Question 10A researcher wishes to test the hypothesis that a persuasive message about our government will change people’s attitudes toward politicians. Each of 20 participants’ attitudes is measured before and after receiving the message. The correct procedure to use is:A.Thettest with independent samples.B.Theztest with independent samples.C.Thettest with matched samples.D.Theztest with matched samples.