A new cream was developed to reduce the irritation caused by poison ivy. To test the effectiveness, researchers placed an ad online asking for volunteers to participate in the study. One hundred subjects replied and were informed that one group would receive the new cream and the other group would receive a cream with no active ingredient. All 100 subjects were exposed to poison ivy. Fifty were then randomly assigned to the group with the new cream, and 50 were randomly assigned to the group with the cream with no active ingredient. After three days, the subjects' level of irritation was measured. Which of the following accurately describes the benefit of comparison in the experiment? O The overall level of irritation can be compared to see if the new cream had a significant effect. O The level of irritation for both groups can be compared to see if the new cream had a significant effect. O The level of irritation in the treatment group only can be compared to see if the new cream had a significant effect O Since one group received a cream with no active ingredient, the researchers will not be able to determine of the new cream is effective.

Determine whether the results appear to have statistical significance, and also determine whether the results appear to have practical significance. One of a botanist's hybridization experiments with peas yielded 732 offspring with 190 of those peas (or 26%) having yellow pods. According to genetic theory, 25% of the offspring peas should have yellow pods. Does the result have statistical significance? According to genetic theory, of the 732 peas would have yellow pods. The difference between the actual number of peas with yellow pods and the expected number of peas with yellow pods is pea(s). This difference to be statistically significant (Type whole n ers.)

Imagine I wanted to study the effectiveness of the Mediterranean diet on people’s memory. I tested a group of people who strictly followed the Mediterranean diet, another group who followed a typical Western diet, and another whose diet I did not change at all. Before the diet changes began, I gave all my participants a memory test. After six weeks of the diet experiment, I had all participants complete the same memory test again to see how scores would change among the three groups.   For this study, identify a parameter and a statistic I might be interested in.

A new cream was developed to reduce the irritation caused by poison ivy. To test the effectiveness, researchers put an ad online asking for volunteers to participate in the study. One hundred subjects replied and were informed that one group would receive the new cream and the other would receive a cream with no active ingredient. All 100 subjects were exposed to poison ivy. Fifty were then assigned to the group with the new cream, and 50 were assigned to the group with the cream with no active ingredient. After three days, technicians recorded the subjects’ level of irritation. Which of the following would benefit this experiment the most? This experiment should be single blind. The subjects will not know which treatment they are receiving to control for the placebo effect, but the technicians need to know which group received the new cream. This experiment should be double blind. Neither the subject nor the technician knows which group is receiving the new cream to control for…

In a 2009 study, a team of researchers recruited 38 men and divided them randomly into two groups - treatment or control. The also recruited 38 women and they randomly placed half the participants into the treatment group and the other half into the control group. One group was given 25 grams of chia seeds twice a day, and the other was given a placebo. The subjects volunteered to be a part of the study. After 12 weeks, the scientists found no significant difference between the groups in appetite or weight loss. Which of the following is true. (i) This is an observational study (ii) Blinding is used in this study because subjects in the control group recieved a placebo, so that htey were blinded to the treatment they recieved.  (iii) We can safely generalize the conclusion (that chia seeds have no significant effect on appetite or weight loss) from the participants to the population at large because randomization is used when assigning participatns to groups.

Many fundraisers ask for donations using email and text messages. A paper describes an experiment to investigate whether the proportion of people who make a donation when asked for a donation by email is different from the proportion of people who make a donation when asked for a donation in a text message. In this experiment, 1.7% of those who received and opened an email request for a donation and 7.8% of those who received a text message asking for a donation actually made a donation. Assume that the people who received these requests were randomly assigned to one of the two groups (email or text message) and suppose that the given percentages are based on sample sizes of 2,000 (the actual sample sizes in the experiment were much larger). (Let p1 be the proportion who make a donation after receiving an email, and p2 be the proportion who make a donation after receiving a text message.) Find the test statistic and P-value. (Use a table or SALT. Round your test statistic to two…

You are interested in testing if there is a difference in weight-loss between 3 popular diet types; low calorie, low fat and low carb. Participants are randomly assigned one of the three groups or a control group. The control group will be told that are participating in a weight-loss study, but will not be following any particular diet. This is to study the placebo effect, weight-loss from just participating in the study. At the start of the study, each participant's weight is recorded in pounds. After 8 weeks they are weighed again, and the weight difference is recorded. A positive value represents a weight loss while a negative value represents a weight gain. Test at 5% significance. Round answers to 3 decimal places. Diet Type Low Calorie Low Calorie Low Calorie Low Calorie Low Calorie Low Fat Low Fat Low Fat Low Fat Low Fat Low Carb Low Carb Low Carb Low Carb Low Carb Control Control Control Control Control Pounds Lost 6.9 4.7 3.5 7.7 5.9 3.8 1.4 3.8 5.2 2 4.9 2.6 2.7 5.6 3.4 1.3…

A pharmaceutical company is testing the effectiveness of its vaccine across two different age brackets. They take a sample and split the participants up into two separate groups. Group A consists of 44 people who are between ages 13 and 18. Group B consists of 58 people between ages 19 and 26. After being administered the vaccine, it was found that 37 people from group A were immune to the virus and 42 people from group B were immune. (this is the same situation from the previous daily) Why do we use the 'pooled proportion' instead of the null hypothesis in the denominator of the test statistic? At a 10% significance level, is there reason to believe there is a difference in vaccine efficacy between Group A and Group B?  explain each step

A psychologist would like to examine the effects of a new drug on the activity level of animals. Three samples of rats are selected with n=5 in each sample. One group gets no drug, one group gets s small dose, and the third group gets a large dose. The psychologist records the activity level for each animal. The data from this experiment are presented below.   No drug Small dose Large dose 5, 3 , 1 , 1 , 5 5, 5, 9, 6, 5 10, 12, 9, 6, 8 =3, SS=16 =6, SS=12 =9, SS=20   Do these data indicate any significant differences among the three groups? Test with α=0.05.                        Compute the effect size and interpret the result.

Hospital floors: Hospital floors are usually bare tiles instead of carpet. Carpets will decrease noise but might increase germ growth.   To study this, researchers installed carpet in 8 of 16 hospital rooms. They randomly selected the rooms to carpet. The other rooms had bare tiles. After two weeks of normal use, they collected air samples from the rooms and counted the bacteria in each sample.   Based on this description of the experiment, which of the following is a part of the experiment design? Check all that apply.   Group of answer choices