Chapter 10 Questions

CHAPTER 10—COMPARISONS INVOLVING MEANS, EXPERIMENTAL DESIGN AND ANALYSIS OF VARIANCE MULTIPLE CHOICE 1. If we are interested in testing whether the mean of items in population 1 is larger than the mean of items in population 2, the a. null hypothesis should state  1 -  2 < 0 b. null hypothesis should state  1 -  2  0 c. alternative hypothesis should state  1 -  2 > 0 d. alternative hypothesis should state  1 -  2 < 0 2.To compute an interval estimate for the difference between the means of two populations, the t distribution a. is restricted to small sample situations b. is not restricted to small sample situations c. can be applied when the populations have equal means d. None of these alternatives is correct. 3.When developing an interval estimate for the difference between two sample means, with sample sizes of n 1 and n 2 , a. n 1 must be equal to n 2 b. n 1 must be smaller than n 2 c. n 1 must be larger than n 2 d. n 1 and n 2 can be of different sizes, 4.To construct an interval estimate for the difference between the means of two populations when the standard deviations of the two populations are unknown and it can be assumed the two populations have equal variances, we must use a t distribution with (let n 1 be the size of sample 1 and n 2 the size of sample 2) a. (n 1 + n 2 ) degrees of freedom b. (n 1 + n 2 - 1) degrees of freedom c. (n 1 + n 2 - 2) degrees of freedom d. n 1 - n 2 + 2 5.When each data value in one sample is matched with a corresponding data value in another sample, the samples are known as a. corresponding samples b. matched samples c. independent samples d. None of these alternatives is correct. 6.Independent simple random samples are taken to test the difference between the means of two populations whose variances are not known, but are assumed to be equal. The sample sizes are n 1 = 32 and n 2 = 40. The correct distribution to use is the a. t distribution with 73 degrees of freedom b. t distribution with 72 degrees of freedom c. t distribution with 71 degrees of freedom d. t distribution with 70 degrees of freedom 7.Independent simple random samples are taken to test the difference between the means of two populations whose standard deviations are not known, but are assumed to be equal. The sample sizes are n 1 = 25 and n 2 = 35. The correct distribution to use is the a. t distribution with 61 degrees of freedom b. t distribution with 60 degrees of freedom

c. t distribution with 59 degrees of freedom d. t distribution with 58 degrees of freedom 8.If two independent large samples are taken from two populations, the sampling distribution of the difference between the two sample means a. can be approximated by a Poisson distribution b. will have a variance of one c. can be approximated by a normal distribution d. will have a mean of one 9.The standard error of is the a. variance of b. variance of the sampling distribution of c. standard deviation of the sampling distribution of d. difference between the two means 10.For testing the following hypothesis at 95% confidence, the null hypothesis will be rejected if     1 -  2  0     1 -  2  0 a. p-value  0.05 b. p-value  0.05 c. p-value  0.95 d. p-value  0.475 11.In the analysis of variance procedure (ANOVA), " factor " refers to a. the dependent variable b. the independent variable c. different levels of a treatment d. the critical value of F 12.The ANOVA procedure is a statistical approach for determining whether or not a. the means of two samples are equal b. the means of two or more samples are equal c. the means of more than two samples are equal d. the means of two or more populations are equal 13.The variable of interest in an ANOVA procedure is called a. a partition b. a treatment c. either a partition or a treatment d. a factor 14. In the ANOVA, treatment refers to a. experimental units b. different levels of a factor c. the dependent variable d. applying antibiotic to a wound 15.In factorial designs, the response produced when the treatments of one factor interact with the treatments of another in influencing the response variable is known as a. main effect b. replication

c. 5 numerator and 114 denominator degrees of freedom d. 6 numerator and 20 denominator degrees of freedom 24.The mean square is the sum of squares divided by a. the total number of observations b. its corresponding degrees of freedom c. its corresponding degrees of freedom minus one d. None of these alternatives is correct. 25.In an analysis of variance problem if SST = 120 and SSTR = 80, then SSE is a. 200 b. 40 c. 80 d. 120 26.The required condition for using an ANOVA procedure on data from several populations is that the a. the selected samples are dependent on each other b. sampled populations are all uniform c. sampled populations have equal variances d. sampled populations have equal means 27.An ANOVA procedure is used for data that was obtained from four sample groups each comprised of five observations. The degrees of freedom for the critical value of F are a. 3 and 20 b. 3 and 16 c. 4 and 17 d. 3 and 19 28.In ANOVA, which of the following is not affected by whether or not the population means are equal? a. b. between-samples estimate of   c. within-samples estimate of   d. None of these alternatives is correct. 29.A term that means the same as the term "variable" in an ANOVA procedure is a. factor b. treatment c. replication d. variance within 30.In order to determine whether or not the means of two populations are equal, a. a t test must be performed b. an analysis of variance must be performed c. either a t test or an analysis of variance can be performed d. a chi-square test must be performed