Calculate the sum of products

A researcher is interested in determining if sleeping more hours the night before an exam will improve student math practice test scores. She randomly divides the class into two groups. One group is instructed to sleep 9 hours. The other group is instructed to sleep 6 hours. Students were asked to complete a practice math test the following day. The researcher then compares the average test score of each group. What is the DV? O the class O the researcher average test score O sleep (9 hours vs 7 hours)

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 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 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. 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…

Empathy means being able to understand what others feel. To see how the brain expresses empathy, researchers recruited 16 couples in their midtwenties who were married or had been dating for at least two years. They zapped the man's hand with an electrode while the woman watched, and measured the activity in several parts of the woman's brain that would respond to her own pain. Brain activity was recorded as a fraction of the activity observed when the woman herself was zapped with the electrode. The women also completed a psychological test that measures empathy. Subject 1 2 3 4 6 7 8 9 10 11 12 13 14 15 16 Empathy Score Brain Activity -0.114 0.39 0.019 0.379 0.010.4120.10.5150.153 0.746 0.250.56 0.214 0.717 0.366 0.778 37 51 44 54 56 67 68 54 48 47 68 65 28 62 26 100 1.2 sub jęct 9 10.0 -20 120 -8,4 Given that the equation for the regression line is ŷ = 0.00683x – 0.03024, what is the residual for subject 9?

Roy's Texaco wants to keep the price of its unleaded gasoline competitive with that of other stations in the area. Roy's is currently charging $1.29 per gallon. To check that the average price for this gasoline for all stations within 12-mile radius is higher than his price, Roy randomly samples the price of unleaded gasoline at ten stations located in this area. He obtains the following data for the price per gallon (in dollars): 1.7, 1.5, 2.6, 2.2, 2.4, 2.3, 2.6, 3.0, 1.4, 2.3 Set up appropriate hypotheses and test them using a significant level of .01.

You want to determine the effect of soap on bacterial colonies. In order to make sure that the environment does not affect your experiment, you divide 13 different petri dishes in half - one side is exposed to soap, the other is a control. You may use R but please show all the steps and codes involved. You measure the number of colonies that grow in each petri dish and come up with the following results: petri dish: 1 2 3 4 5 6 7 8 9 10 11 12 13soap: 10 5 7 10 19 11 13 17 19 8 11 10 16control: 20 17 11 17 26 18 21 25 24 17 17 17 21 Perform a complete hypothesis test to see if there is a difference in bacterial colonies between the soap and control dishes.

Empathy means being able to understand what others feel. To see how the brain expresses empathy, researchers recruited 16 couples in their midtwenties who were married or had been dating for at least two years. They zapped the man's hand with an electrode while the woman watched, and measured the activity in several parts of the woman's brain that would respond to her own pain. Brain activity was recorded as a fraction of the activity observed when the woman herself was zapped with the electrode. The women also completed a psychological test that measures empathy. 13 14 15 36 113 2 7 8 9 10 5 6 53 55 59 58 53 Brain Activity -0.1010.398 0.017 0.368 0.02 0.424 0.09 0.5160.1530.737 0.252 0.568 0.217 0.712 0.359 0.776 Subject 1 3 4 11 12 16 Empathy Score 42 55 40 48 43 68 61 18 59 1.2 sub ject 5 e 10,0 20 120 -8,4 Given that the equation for the regression line is y = 0.00635x +0.00218, what is the residual for subject 5? ANSWER:

the brand manager for a toothpaste brand must plan a campaign designed to increase brand recognition. H1e wants to first demonstrate the percentage of adults who have heard of the product. How many adults must he survey in order to be 95 percent confident that his estimate is within 5 percentage points of the true population percentage? n=?