The article “Puppy Love? It’s Real, Study Says” (USA TODAY, April 17, 2015) describes a study into how people communicate with their pets. The conclusion expressed in the title of the article was based on research published in Science (“Oxytocin-Gaze Positive Loop and the Coevolution of Human-Dog Bonds,” April 17, 2015). Researchers measured the oxytocin levels (in picograms per milligram, pg/mg) of 22 dog owners before and again after a 30-minute interaction with their dogs. (Oxytocin is a hormone known to play a role in parent-child bonding.) The difference in oxytocin level (before – after) was calculated for each of the 22 dog owners. Suppose that the
- a. Explain why the two samples (oxytocin levels before interaction and oxytocin levels after interaction) are paired.
- b. Assume that it is reasonable to regard the 22 dog owners who participated in this study as representative of dog owners in general. Do the data from this study provide convincing evidence that there is an increase in mean oxytocin level of dog owners after 30 minutes of interaction with their dogs? State and test the appropriate hypotheses using a significance level of 0.05.
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Introduction To Statistics And Data Analysis
- What is an experiment?arrow_forwardWhat is meant by the sample space of an experiment?arrow_forwardA researcher conducts an independent-measures study to examine how the brain chemical serotonin is related to aggression. One sample of rats serves as a control group and receives a placebo that does not affect normal levels of serotonin. A second sample of rats, low serotonin group, receives a drug that lowers brain levels of serotonin. Then, the researcher tests the animals by recording the number of aggressive responses each of the rats display. See the data below. Is there a significant difference between the control group and the low serotonin group regarding the number of aggressive responses? Control Low Serotonin n = 10 n = 15 M = 14 M = 19 SS = 180.5 SS = 130 Perform a hypothesis test using independent-measures t-test. Use a two-tailed…arrow_forward
- Source: Centers for Disease Control and Prevention. [Vital Signs: binge Drinking among women and high school girls - United States 2011]. MMWR 2013;62:pg 9-13. http://www.cdc.gov/mmwr/pdf/wk/mm6201.pdf The article referenced says that when women aged 25-34 binge drink they have on average 7.2 drinks. I'm wondering if women in Laramie are different than the national average. Assume the standard deviation is 0.42 drinks. I sample 9 women who have done binge drinking, and their average is 5.1 drinks. Can I say at the 0.05 significance level that the average is not equal to 7.2? Hg:X = 7.2 HA:X + 7.2 Ho:x + 7.2 HAix = 7.2 Ho:u - 5.1 Ho: = 7.2 Họ:* 5.1 Ho:u + 7.2 HA 5.1 HA:H 7.2 HA:H - 5.1 HA:H - 7.2 P-value ODo not answer until you choose an a ODo not answer until you choose an a You cannot answer this until you choose an a O You cannot answer this until you choose an aarrow_forwardWhat is the answer to question 15?arrow_forwardAfter the 2010 earthquake in Haiti, many charitable organizations conducted fundraising campaigns to raise money for emergency relief. Some of these campaigns allowed people to donate by sending a text message using a cell phone to have the donated amount added to their cell-phone bill. The report "Early Signals on Mobile Philanthropy: Is Haiti the Tipping Point?" (Edge Research, 2010) describes the results of a national survey of 1526 people that investigated the ways in which people made donations to the Haiti relief effort.The report states that 17% of Gen Y respondents (those born between 1980 and 1988) and 14% of Gen X respondents (those born between 1968 and 1979) said that they had made a donation to the Haiti relief effort via text message. The percentage making a donation via text message was much lower for older respondents. The report did not say how many respondents were in the Gen Y and Gen X samples, but for purposes of this exercise, suppose that both sample sizes were…arrow_forward
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- “The US Centers for Disease Control and Prevention said about 72 million Americans—nearly one out of every four of the country’s 304 million residents—are considered obese. Millions more are designated as overweight.” The American trend toward obesity has prompted many physicians to offer weight-loss programs to their patients. [Source: Price, W. T. “Physicians Get into the Weight-Loss Business.” Florida Today, July 7, 2008.] A physician conducted an experimental study to compare the effectiveness of four different weight-loss programs. In the study, 64 obese adults were randomly assigned to the four programs so that each program had 16 adults. The programs lasted for six months. The weights of the subjects were measured before and after the programs, and each subject’s weight loss was computed in pounds. The following table summarizes the results of the study, giving the number of observations and the sample mean and variance of the subjects’ weight loss in each program.…arrow_forwardWhen asked, "How much time will you require to complete this task?" cognitive theory posits that people will typically underestimate the time required. Would the opposite theory hold if the question was phrased in terms of how much work could be completed in a given amount of time? This was the question of interest to researchers writing in Applied Cognitive Psychology (Vol. 25, 2011). For one study conducted by the researchers, each in a sample of 40 University of Oslo students was asked how many minutes it would take to read a 32-page report. In a second study, 42 students were asked how many pages of a lengthy report they could read in 48 minutes. (The students in either study did not actually read the report.) Numerical descriptive statistics (based on summary information published in the article) for both studies are provided in the accompanying table. Sample size, n Sample mean, Sample standard deviation, s Estimated Time (minutes) 40 60 41 Estimated Number of Pages 42 28 14 a.…arrow_forwardIt appears that there is some truth to the old adage “That which doesn’t kill us makes us stronger.” Seery, Holman, and Silver (2010) found that indi- viduals with some history of adversity report better mental health and higher well-being compared to people with little or no history of adversity. In an attempt to examine this phenomenon, a researcher surveys a group of college students to determine the negative life events that they experienced in the past 5 years and their current feeling of well-being. For n = 18 participants with 2 or fewer negative experi- ences, the average well-being score is M = 42 with SS = 398, and for n = 16 participants with5 to 10 negative experiences the average score is M = 48.6 with SS = 370.a. Is there a significant difference between the two populations represented by these two samples? Use a two-tailed test with α = .05arrow_forward
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