Suppose two subject scores (Python, Java) for five students have the following values:   Python Java Student 1 4 6 Student 2 2 5 Student 3 10 8 Student 4 7 5 Student 5 4 3 Find covariance of Python and Java. (Your answer should be the nearest to one-hundredth, e.g., 123.45)

A researcher thinks some social media sites are more prone to narcissistic behavior (excessive posting) than others. To examine the relationship between narcissism and social media, she recruits users of three different social media sites (Facebook, Twitter and Instagram), follows them for 24 hours and records the number of posts made by each user. The number of posts is given in the table below. Twitter Facebook Instagram 10 7 14 10 8. 10 10 10 11 9. www. 12 wwww. 11 13 12 8. 7 8. 11 8 10 12 11 11 a. Perform a complete hypothesis test to determine whether there are any significant differences among the three groups. Test at the .05 level of significance. SHOW ALL YOUR WORK b. Do you need to perform post hocs? Explain but do not compute the post hocs. C. Compute effect size. d. Summarize your findings in a source table. e. Write an interpretation of our results in APA-format (include means and SDs in your interpretation)

Give an explanation why this statement is either true or false:   Portfolio contains n assets. Therefore, portfolio variance for this portfolio is the function of 2n covariances and n variances.

A researcher is interested in the affects that a person’s avatar (i.e. visual representation of oneself) has on the number of profile views on Facebook.com.  The average number of individual personal profile views is known to be 230 views per day (excluding bands, artists, etc.).  The researcher creates 36 fictitious profiles that contain roughly the same information but the picture (avatar) is an animated .gif of a smiling face (36 faces randomly selected from a compilation of faces judged to be of average attractiveness).  The results showed that of the 36 profiles the average number of views was 250 with a standard deviation of 60.  Test the hypothesis that the average number of views for a smiling face gif is significantly different than the usual number of personal profile views.

A survey was conducted in 1990 asking American high school students to name their favorite subject inschool. This survey found that, in 1990, the following proportions of students named each subject astheir favorite: 30% History, 25% Math, 20% English, 15% Biology, 10% Chemistry. A researcher in theyear 2020 conducts an identical survey, in order to see if students’ favorite subjects have shifted overthe 30 years that have passed since the 1990 study was done. The researcher gives the survey to n=60high school students, and gets the following observed frequencies and expected frequencies. FREQUENCY   History        Math      English     Biology     Chemistry    TOTAL      fo                    20          18            10                5               7              60      fe           (.30)(60) =  (.25)(60) =   (.20)(60) =  (.15)(60) =  (.10)(60) =                       18                15             12                9                6         60   What is the χ2critical that you…

10.5) Assume a pond contains 90 fish: 70 orange, 19 silver, and 1 red. A contestant pays $0.55 to randomly catch one fish and receives $0.35 if the fish is orange, $1.15 if the fish is silver, and $15.00 if the fish is red. How much (on average) does the carnival gain on each play? (If the carnival looses money, enter a negative dollar amount)

Foofy obtained a significant Fobt from an experiment with five levels. She therefore concludes that changing every condition of the independent variable results in a significant change in the dependent variable. (a) Is she correct? Why or why not? (b) What must she now do?

The following table lists body temperatures of seven subjects at 8 AM and at 12 AM. The data are matched pairs because each pair of temperatures is measured from the same person. Using the data, it is possible to test for no difference between body temperatures at 8 AM and 12 AM by using the sign test or the Wilcoxon signed-ranks test. In what sense does the Wilcoxon signed-ranks test incorporate and use more information than the sign test? Temperature (°F) at 8 AM Temperature (°F) at 12 AM Choose the correct answer below. 98.0 97.6 97.2 98.0 97.0 98.0 98.2 97.0 98.8 97.6 98.0 97.7 98.8 97.6 O A. The sign test requires that the population is normally distributed, while the Wilcoxon signed-ranks test only requires that the population distribution is approximately symmetric. OB. The sign test uses only the signs of the differences, but the Wilcoxon signed-ranks test uses ranks that are affected by the magnitudes of the differences. O C. The sign test uses only the magnitudes of the…

If there are 65 successes of 150 trials in the one group, and 115 successes of 200 in another, test if the groups significantly different? Use ? = 0.05.