A developmental psychologist is studying bonding between healthy newborn babies and immediate family members. He wants to know if one-week-old infants use smell to recognize their fathers. To investigate, he selects a random sample of one-week-old infants. Each infant is presented with a garment worn by his or her father and two garments worn by unrelated men. The psychologist observes which garment each of the infants orients toward. The resulting data are summarized in the following table that shows the number of infants who oriented toward each of the three garments.   What is are the degrees of freedom for this experiment?     4     3     1     2

A research article on the effect of multitasking on grade performance describes an experiment in which 62 undergraduate business students were randomly assigned to one of two experimental groups. Students in one group were asked to listen to a lecture but were told that they were permitted to use cell phones to send text messages during the lecture. Students in the second group listened to the same lecture but were not permitted to send text messages. Afterwards, students in both groups took a quiz on material covered in the lecture. Data from this experiment are summarized in the accompanying table.

Suzanne Zeedyk, a developmental psychologist at Dundee University’s School of Psychology, conducted a pilot study in which parents started a half-hour walk with their infants in a parent-facing or an away-facing stroller and then switched to the other type of stroller midway. Her results suggest that parents talked less to the babies, the babies had higher heart rates, and they were less likely to fall asleep in away-facing strollers than in parent-facing strollers. You are interested in testing the hypothesis that babies who travel in parent-facing strollers have different expressive vocabularies than babies who travel in away-facing strollers. You randomly assign 13 newborns to parent-facing strollers and 13 newborns to away-facing strollers. You then test the babies’ expressive vocabularies at age 36 months using the Expressive Vocabulary Test (EVT), which is designed primarily to assess children’s expressive vocabulary. The sample means and sums of squares of the scores for each of…

Suzanne Zeedyk, a developmental psychologist at Dundee University’s School of Psychology, conducted a pilot study in which parents started a half-hour walk with their infants in a parent-facing or an away-facing stroller and then switched to the other type of stroller midway. Her results suggest that parents talked less to the babies, the babies had higher heart rates, and they were less likely to fall asleep in away-facing strollers than in parent-facing strollers. You are interested in testing the hypothesis that babies who travel in parent-facing strollers have different receptive vocabularies than babies who travel in away-facing strollers. You randomly assign 18 newborns to parent-facing strollers and 18 newborns to away-facing strollers. You then test the babies’ receptive vocabularies at age 18 months using the Peabody Picture Vocabulary Test—Revised (PPVT-R), which is designed primarily to assess children’s receptive vocabulary. The sample means and sums of squares of the…

A psychologist conducted a survey of the attitude towards the sustainability of American energy consumption with 380380 randomly selected individuals several years ago. The psychologist believes that these attitudes have changed over time. To test this he randomly selects 380380 individuals and asks them the same questions. Can the psychologist confirm his theory that the attitudes have changed from the first survey to the second survey? Attitude 1st Survey 2nd Survey Optimistic 6%6% 7%7% Slightly Optimistic 30%30% 26%26% Slightly Pessimistic 21%21% 24%24% Pessimistic 43%43% 43%43% Copy Data Step 4 of 10 :   Find the expected value for the number of respondents who are optimistic. Round your answer to two decimal places.

A paper investigated the driving behavior of teenagers by observing their vehicles as they left a high school parking lot and then again at a site approximately  1 2  mile from the school. Assume that it is reasonable to regard the teen drivers in this study as representative of the population of teen drivers. MaleDriver FemaleDriver 1.4 -0.2 1.2 0.5 0.9 1.1 2.1 0.7 0.7 1.1 1.3 1.2 3 0.1 1.3 0.9 0.6 0.5 2.1 0.5 (a) Use a .01 level of significance for any hypothesis tests. Data consistent with summary quantities appearing in the paper are given in the table. The measurements represent the difference between the observed vehicle speed and the posted speed limit (in miles per hour) for a sample of male teenage drivers and a sample of female teenage drivers. (Use ?males − ?females. Round your test statistic to two decimal places. Round your degrees of freedom down to the nearest whole number. Round your p-value to three decimal places.) t =   df =…

In a study of the Gouldian finch, Griffith et al. (2011) looked at stress caused by having an incompatible mate. There are two genetically distinct types of Gouldian finches, one having a red face and the other having a black face. Previous experiments have shown that female finches have a strong preference for mating with males with the same face color as themselves and that when different face types of finch mate with one another, their offspring are less likely to survive than when both parents are the same type. Researchers paired females sequentially with males of both types in random order.In other words, each female bred twice once with a compatible male and once with an incompatible male. Each time, females produced a brood of young with the assigned male. For each pairing, the researchers measured the blood corticosterone concentration (in units of ng/ml) as an index of the amount of stress the females experienced. The corticosterone data for 43 females are given below:…

A seven-year medical research study reported that women whose mothers took the drug DES during pregnancy were twice as likely to develop tissue abnormalities that might lead to cancer as were women whose mothers did not take the drug. a. This study compared two What were the populations? b. Do you suppose the data were obtained in a survey or an experiment? c. For the population of women whose mothers took the drug DES during pregnancy, a sample of 3980 women showed that 63 developed tissue abnormalities that might lead to Provide a descriptive statistic that could be used to estimate the number of women out of 1000 in this population who have tissue abnormalities. d. For the population of women whose mothers did not take the drug DES during pregnancy, what is the estimate of the number of women out of 1000 who would be expected to have tissue abnormalities? e. Medical studies often use a relatively large sample (in this case.3980).Why?

Which of the independent variables retains the strongest association with the number of children a respondent has when all other variables in the model are controlled?  What is that association?  Which has the weakest when other variables are controlled?