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Use the univ data frame that you have downloaded and read in to your R environment. The questions below are numbered A, and B, Please use those letters in your answers. That is Write A and start the answer for that question on the following line, and so on. Write R code to build a model with score as the response variable and hours_studied as the explanatory variable and to print the variances of the response variable and model values (4 points) What proportion of the variability in the response variable does the model explain? (2 points)

Use the “univ” data frame that you created based on the instructions. Write R code to generate a point plot of the effect of hours_studied on score. Do not annotate it. Explain why you placed each variable on a specific axis.    

Use the “univ” data frame that you created based on the instructions. Write R code to generate a point plot (scatterplot) of score on the y-axis and hours_studied on the x-axis. Do not provide a model annotation.   The general overall relationship between these two variables is that   

Use the “univ” data frame that you created based on the instructions. Show R code to generate a single plot to study the distribution of score for each school separately  On comparing the general trend of the scores of students from the three schools select that option most consistent with the plot:

Use the “univ” data frame that you created based on the instructions. Write R code to compute the average score across all students. Name the resulting column avg_score.  

Use the “univ” data frame that you created based on the instructions. Write R code to generate a point plot of the effect of hours_studied on score. Color each point based on the school. Do not annotate with a model.      

The figure below shows ten rows from a data frame with more than 500 rows. Select all options that represent variables in the data frame. Remember, you must select al correct options. No partial cresit will be awarded. You get points only if you select all correct options and do not select any of the incorrect options. date       pce    pop psavert uempmed unemploy                  1 1967-07-01  507. 198712    12.6     4.5     2944 2 1967-08-01  510. 198911    12.6     4.7     2945 3 1967-09-01  516. 199113    11.9     4.6     2958 4 1967-10-01  512. 199311    12.9     4.9     3143 5 1967-11-01  517. 199498    12.8     4.7     3066 6 1967-12-01  525. 199657    11.8     4.8     3018 7 1968-01-01  531. 199808    11.7     5.1     2878 8 1968-02-01  534. 199920    12.3     4.5     3001 9 1968-03-01  544. 200056    11.7     4.1     287710 1968-04-01  544  200208    12.3     4.6     2709

8. A block has a mass of 120 g and volume of 50.0 cm³. What is its density?

1. Why is the SI system of units preferred in science?

9. Round 0.00456789 to 3 significant figures.