This study source was downloaded by 100000861308886 from CourseHero com on 02 26 2023 19 56 47 GMT 06 00 https www coursehero com file 6508717 test10b other form Test 10BAP Statistics Name Directions Work on these sheets Answer completely but be concise A normal probability table is attached 1 In formulating hypotheses for a statistical test of significance the null hypothesis isoftenA a statement that there is no effect or no difference B the probability of observing the data you actually obtained C a statement that the data are all 0 D 0 05 2 An agricultural researcher plants 25 plots with a new variety of corn A 90 confidenceinterval for the average yield for these plots is found to be 162 72 4 47 bushels peracre Which of the following would produce a confidence interval with a smaller marginof error than this 90 confidence interval A planting only five plots rather than 25 since five are easier to manage and control B planting 100 plots rather than 25 C computing a 99 confidence interval rather than a 90 confidence interval the increase in confidence indicates that we have a better interval D none of the above 3 A small company consists of 25 employees As a service to the employees the company arranges for each to have a complete physical for free Among other things the weight of each employee is measured the mean weight is found to be 165 pounds The population standard deviation is 20 pounds It is believed that a mean weight of 160pounds would be normal for this group To see if there is evidence that the mean weightof the population of all employees of the company differs significantly from 160 thehypotheses H0 160 Ha 160 are tested You obtain a P value of less than 0 1056 Which of the following is true A At the 5 significance level you have proved that H0 is true B You have failed to obtain any evidence for Ha C At the 5 significance level you have failed to prove that H0 is true and a larger sample size is needed to do so D None of the above 4 The mean area of the several thousand apartments in a new development is advertised to be 1250 square feet A tenant group thinks that the apartments are smaller than advertised They hire an engineer to measure a sample of apartments to test their suspicion The appropriate null and alternative hypotheses H0 and Ha for A are H0 1250 Ha 1250 B are H0 1250 Ha 1250 C are H0 1250 Ha 1250 D cannot be specified without knowing the size of the sample used by the engineer 5 An agricultural researcher plants 25 plots with a new variety of corn The average yield for these plots is J 150 bushels per acre Assume that the yield per acre for the new variety of corn follows a normal distribution with unknown mean and that a 95 confidence interval for is found to be 150 3 29 Which of the following is true A A test of the hypotheses H0 150 Ha 150 would be rejected at the 0 05 level B A test of the hypotheses H0 150 Ha 150 would be rejected at the 0 05 level C A test of the hypotheses H0 160 Ha 160 would be rejected at the 0 05 level D No hypothesis test can be conducted because we do not know s Chapter 101Test 10B This study source was downloaded by 100000861308886 from CourseHero com on 02 26 2023 19 56 47 GMT 06 00 https www coursehero com file 6508717 test10b other form 6 In tests of significance about an unknown parameter of some population which of thefollowing is considered strong evidence against the null hypothesis A The value of an estimate of the unknown parameter based on a simple randomsample from the population is not equal to zero B The value of an estimate of the unknown parameter based on a simple randomsample from the population is equal to zero C We observe a value of an estimate of the unknown parameter based on a simplerandom sample from the population that is very consistent with the null hypothesis D We observe a value of an estimate of the unknown parameter based on a simplerandom sample from the population that is very unlikely if the null hypothesis istrue 7 A procedure for approximating sampling distributions which can then be used toconstruct confidence intervals when theory cannot tell us their shape isA least squares B the bootstrap C residual analysis D standardization 8 A medical researcher is working on a new treatment for a certain type of cancer Theaverage survival time after diagnosis on the standard treatment is two years In an early trial she tries the new treatment on three subjects who have an average survival time after diagnosis of four years Although the survival time has doubled the results are not statistically significant even at the 0 10 significance level Suppose in fact that the new treatment does increase the mean survival time in the population of all patients with this particular type of cancer The researcher hasA committed a type I error B committed a type II error C incorrectly used a level 0 10 test when she should have used a 0 05 level test D incorrectly used a level 0 10 test when she should have computed the P value Use the following to answer question 9 A researcher wishes to determine if students are able to complete a certain pencil and paper maze more quickly while listening to classical music Suppose the time in seconds needed for high school students to complete the maze while listening to classical music follows a normal distribution with mean and standard deviation s 4 Suppose also that in the general population of all high school students the time needed to complete the maze without listening to classical music follows a normal distribution with mean 40 and standard deviation s 4 The researcher therefore decides to test the hypothesesH0 40 Ha 40To do so the researcher has 10 000 high school students complete the maze with classical music playing The mean time for these students is J 39 8 seconds and the P value is less than 0 0001 9 Suppose that two high school students decide to see if they get the same results as the researcher They both take the maze while listening to classical music The mean of their times is J 39 8 seconds the same as that of the researcher It is appropriate to conclude which of the following A The students have reproduced the results of the researcher and their P value will be the same as that of the researcher B The students have reproduced the results of the researcher but their P value will be slightly smaller than that of the researcher C The students will reach the same statistical conclusion as the researcher but their Pvalue will be a bit different than