A random experiment was run 23 times with groups of 24 mice. Each time the experiment was run, 4 mice were initially infected with a disease; the remaining mice were susceptible to contracting the disease.  After one day, they measured the number of number of newly infected mice (not including those originally infected). They found the following frequency table: Newly infected mice Newly infected mice 4 5 6 7 8 9 10 11 Frequency 1 2 2 6 5 4 2 1 Determine the expected probability of transmission for this particular variant of disease.

Researchers studying starfish collected two independent random samples of 40 starfish. One sample came from an ocean area in the north, and the other sample came from an ocean area in the south. Of the 40 starfish from the north, 6 were found to be over 8 inches in length. Of the 40 starfish from the south, 11 were found to be over 8 inches in length. Which of the following is the test statistic for the appropriate test to investigate whether there is a difference in proportion of starfish over 8 inches in length in the two ocean areas (north minus south) ?     6−11640+1140√ A 6−110.1540+0.27540√ B 0.15−0.275(0.15)(0.275)(140+140)√ C 0.15−0.275(0.2125)(0.7875)(140+140)√ D 0.15−0.275(0.2125)(0.7875)140+140√

An article reported the results of a peer tutoring program to help children learn to read. In the experiment, the children were randomly divided into two groups: the experimental group received peer tutoring along with regular instruction, and the control group received regular instruction with no peer tutoring. There were n1 = n2 = 30 children in each group. The Gates-MacGintie Reading Test was given to both groups before instruction began. For the experimental group, the mean score on the vocabulary portion of the test was x1 = 344.5, with sample standard deviation s1 = 49.7. For the control group, the mean score on the same test was x2 = 353.8, with sample standard deviation s2 = 50.1. Use a 5% level of significance to test the hypothesis that there was no difference in the vocabulary scores of the two groups before the instruction began.   (a) What is the level of significance?State the null and alternate hypotheses. H0: ?1 = ?2; H1: ?1 ≠ ?2H0: ?1 = ?2; H1: ?1 < ?2    H0: ?1 =…

One cable company claims that it has excellent customer service. In fact, the company advertises that a technician will arrive within 60 minutes after a service call is placed. One frustrated customer believes this is not accurate, claiming that it takes over 60 minutes for the cable technician to arrive. The customer asks a simple random sample of 25 other cable customers how long it has taken for the cable technician to arrive when they have called for one. The sample mean for this group is 63.4 minutes with a standard deviation of 15.1 minutes. Assume that the population distribution is approximately normal. Test the customer's claim at the 0.025 level of significance. Step 1 of 3: State the null and alternative hypotheses for the test. Fill in the blank below. Но : и 3 60 60 11: "H E Tables Кeyрad Answer Keyboard Shortcuts O >

In a study, a large sample representative of the households in the US were asked about their smoking habits. The data suggested that current smokers were on average much healthier than those who recently stopped smoking. Investigators concluded that smoking does not necessarily lead to worse health outcomes. Consider the following statements. Select the ones you agree with, based on the information given. Group of answer choices A.In a randomized experiment, smoker and non-smoker groups are similar across all potential characteristics. b.The conclusions were justified by the data. c.This is an observational study. d.This study is a randomized controlled experiment. e.The results can be explained due to confounding. Current smokers are different from those who recently stopped in ways that are related to health outcomes.

An article reported the results of a peer tutoring program to help children learn to read. In the experiment, the children were randomly divided into two groups: the experimental group received peer tutoring along with regular instruction, and the control group received regular instruction with no peer tutoring. There were n1 = n2 = 36 children in each group. The Gates-MacGintie Reading Test was given to both groups before instruction began. For the experimental group, the mean score on the vocabulary portion of the test was x1 = 344.5, with sample standard deviation s1 = 45.5. For the control group, the mean score on the same test was x2 = 334.3, with sample standard deviation s2 = 48.5. Use a 10% level of significance to test the hypothesis that there was no difference in the vocabulary scores of the two groups before the instruction began. (a) What is the level of significance?State the null and alternate hypotheses. H0: ?1 = ?2; H1: ?1 > ?2H0: ?1 = ?2; H1: ?1 < ?2    H0: ?1 ≠…

A researcher was interested in comparing the amount of time spent watching television by women and by men. Independent simple random samples of 14 women and 17 men were selected, and each person was asked how many hours he or she had watched television during the previous week. The summary statistics are as follows.women: x1=12.6 hrs, s1=3.9 hrs, n1=14.0  men : x2 = 14.0 hrs, s2= 5.2 hrs, n2= 17 Construct a 99% confidence interval for  the difference between the mean amount of time spent watching television for women and the mean amount of time spent watching television for men.

According to a study on the effects of smoking by pregnant women on rates of asthma in their children, for expectant mothers who smoke 20 cigarettes per day, 22.2% of their children developed asthma by the age of two in the US. A biology professor at a university would like to test if the percentage is different in another country. She randomly selects 319 women who only deliver one child and smoke 20 cigarettes per day during pregnancy in that country and finds that 82 of the children developed asthma by the age of two. In this hypothesis test, Do the hypothesis test. Use a level of significance of a = 0.05; Use the unrounded values in Excel to find the answers for #3 and #4 1. This is an example of 2. Find the standard error. 3. Find the z value. Question 10 V a hypothesis test.

A graduate student is interested in how viewing different types of scenes affects working memory. For his study, he selects a random sample of 36 adults. The subjects complete a series of working memory tests before and after walking in an urban setting. Before the walk, the mean score on the test of working memory was 9.1. After the walk, the mean score was 1.4 higher. The graduate student has no presupposed assumptions about how viewing different types of scenes affects working memory, so he formulates the null and alternative hypotheses as: H00 : μDD = 0 H11 : μDD ≠ 0 Assume that the data satisfy all of the required assumptions for a repeated-measures t test. The graduate student calculates the following statistics for his hypothesis test: Mean difference (MDD) 1.4 Estimated population standard deviation of the differences (s) 1.6 Estimated standard error of the mean differences (sMDMD) 0.2667 Degrees of freedom (df) 35 The t statistic 5.25 The critical values of t…

Researchers investigate how the presence of cell phones influence the quality of human interaction.  Subjects are randomly selected from a population and divided into an experimental group that is asked to leave their phones in the front of the room and a control group that are not asked to leave their cell phones at the front of the room.  Subjects are left alone for 10 minutes and then asked to take a survey designed to measure quality of interactions they had with others in the experiment.  What statistical test is appropriate?