A researcher hypothesized that university students gain weight during their first year of study, and studied a sample of 100 students at UBC. The research team then repeated the same study on 299 additional universities (100 students from each) across North America. Assuming the null hypothesis is correct, that the first year of university study is not associated with any change in weight, how many universities (out of the 300 tested) would be expected to show significant weight gain at alpha=D0.05? O 15 O depends on the p-value O none

A study indicates that CB radio use speeds up activity in the brain. As part of a randomized crossover study, 36 participants were fitted with a CB radio device on each ear and then underwent two positron emission topography, or PET, scans to measure brain glucose metabolism. During one scan, the CB radios were both turned off. During the other scan, an automated 40- minute muted signal was sent to the radio on the right ear. The order of when the signal was received (for the first or second scan) was randomized. Comparison of the PET scans showed a minor increase in activity in the part of the brain closest to the antenna during the transmission of the automated signal. Was this an observational study or an experiment? Explain why. O The study is an observational study because the reseashers cannot control the response variable during the signal. O The study is an observational study because the researchers only observe values of the response and explanatory variables. O The study is…

Dr. Ingrid is conducting an experiment to see whether time spent reading is related to poor vision. To do so, she creates three groups and randomly assigns 17 participants to each: the first group reads for 30 min a day, the second group reads for 1hr a day, and the third group reads for 1.5 hrs a day. Dr. Ingrid plans on using a one-way ANOVA to analyze the results of her experiment. If Dr. Ingrid has set alpha to .01, what will be her critical value of F?

A study of fox rabies in southern Germany gave the following information about different regions and the occurrence of rabies in each region. A random sample of n1 = 16 locations in region 1 gave the following information about the number of cases of fox rabies near that location. x1:   Region I Data 3 7 8 7 5 8 8 1 3 3 3 2 5 1 4 6 A second random sample of n2 = 15 locations in region II gave the following information about the number of cases of fox rabies near that location. x2:   Region II Data 4 2 4 1 3 8 5 4 4 4 2 2 5 6 9   Note: If a two-sample t-test is appropriate, for degrees of freedom d.f. not in the Student's t table, use the closest d.f. that is smaller. In some situations, this choice of d.f. may increase the P-value by a small amount and therefore produce a slightly more "conservative" answer.Use a calculator with sample mean and sample standard deviation keys to find  x1  and s1 in region I, and x2 and s2 in region II. (Round your answers to two…

carefully watched over a number of feedings. If it used its right paw more than half the time to activate the tube, it was defined to be “right-pawed." Observations of this sort showed that 67% of mice belonging to strain A/J are right-pawed. A similar protocol was followed on a sam- ple of thirty-five mice belonging to strain A/HeJ. Of those thirty-five, a total of eighteen were eventually classified as right-pawed. Test whether the proportion of right-pawed mice found in the A/HeJ sample was significantly differ- ent from what was known about the A/J strain. Use a two- sided alternative and let 0.05 be the probability associated with the critical region.

Prior to an intensive TV advertising campaign, the producers of Nike athletic shoes find that 29 of a random sample of 200 upper-income adults are aware of their new leisure shoe line.  A second random sample of 300 such adults is taken after the campaign.  Now 96 of the persons sampled can identify the new line.  Is the increase in the proportion of upper income adults showing brand awareness significant?  Test the claim using alpha = .05.

A study of fox rabies in a country gave the following information about different regions and the occurrence of rabies in each region. A random sample of  n1 = 16  locations in region I gave the following information about the number of cases of fox rabies near that location. x1:    Region I Data 1 9 9 9 7 8 8 1 3 3 3 2 5 1 4 6 A second random sample of  n2 = 15  locations in region II gave the following information about the number of cases of fox rabies near that location. x2:    Region II Data 1 1 5 1 6 8 5 4 4 4 2 2 5 6 9   What is the value of the sample test statistic? (Test the difference μ1 − μ2. Do not use rounded values. Round your final answer to three decimal places.)

A random selection of volunteers at a research institute have been exposed to a typical cold virus. After they started to have cold symptoms, 15 of them were given multivitamin tablets formulated to fight cold symptoms. The remaining 15 volunteers were given placebo tablets. For each individual, the length of time taken to recover from the cold is recorded. At the end of the experiment the following data are obtained. Days to recover from a cold Treated with multivitamin 4.9. 3.9, 4.9. 7.3, 3.7, 5.7, 4.3, 6.1, 4.9, 5.4, 7.7, 7.3, 4.6, 4.3, 4.6 Treated with placebo 5.1, 5.3, 5.3, 1.6, 1.6, 4.8, 4.4, 3.3, 3.7, 5.2, 5.5, 5.8, 6.5, 1.5, 5.4 Send data to calculator Send data to Excel It is known that the population standard deviation of recovery time from a cold is 1.8 days when treated with multivitamin tablets, and the population standard deviation of recovery time from a cold is 1.5 days when treated with placebo tablets. It is also known that both populations are approximately normally…

A study indicates that CB radio use speeds up activity in the brain. As part of a randomized crossover study, 36 participants were ntted with a CB radio device on each ear and then underwent two positron emission topography, or PET, scans to measure brain glucose metabolism. During one scan, the CB radios were both turned off. During the other scan an automated 40- minute muted signal was sent to the radio on the right ear. The order of when the signal was received (for the first or second scan) was randomized. Comparison of the PET scans showed a minor increase in activity in the part of the brain closest to the antenna during the transmission of the automated signal. Was this an observational study or an experiment? Explain why. O The study is an observational study because the researchers cannot control the response variable during the signal. O The study is an observational study because the researchers only observe values of the response and explanatory variables. O The study is…

Suppose we are developing a new drug that is supposed to improve the recovery time of an illness. We want to investigate if this is true. We conduct an experiment: we randomize twenty participants into two groups of size n = 10 each. In one group, we give the participants the drug. In the other group, we give them a placebo. We measure the recovery time of the participants in days. We observe the following data: • In the group given the drug, we observe recovery times (yı,..., Y10) = (15, 10, 13, 7,9, 8, 21,9, 14, 8), with ĝ1 = 11.4. • In the group given the placebo, we observe recovery times (yı1,..., Y20) = (15, 14, 12, 8, 14, 7, 16, 10, 15, 12) with j2 = 12.3. Assume that the data in each group follow Normal(µ1,0²) and Normal(42, o²) distributions respec- tively for the drug and placebo groups, o2 15. We want to test the following hypothesis: Ho : µ1 – 12 = 0 versus HA: µ1 – 42 < 0, using the test statistic T(Y) = Y1 – Ý2. a) Define the rejection region as {y : ĝı – 2 < c1} where ci…