Test1_solutions_F23

{ Special instructions Your final numerical answers should be given to 3 significant digits (e.g. 0.0329). How- ever, between steps/parts you should carry more decimal places to avoid rounding errors. For each question, make sure you show your work. An incorrect answer with no work shown will receive zero marks. However, an incorrect answer could still receive credit if you’ve shown your work. Answer the questions in the spaces provided. You may use the last pages of the test for any additional work you would like to be graded. If you use this space, make it as clear as possible which question(s) your work relates to. The exam consists of 18 questions for a total of 35 marks. The number of marks available per question is indicated in [square brackets]. Only non-graphing non-programmable calculators are permitted. GOOD LUCK!

Selected Formulae Q 2 = x ( n 2 ) + x ( n 2 +1 ) 2 or Q 2 = x ( n +1 2 ) LL = Q 1 − 1 . 5 IQR UL = Q 3 + 1 . 5 IQR ¯ x = ∑ n i =1 x i n s 2 x = ∑ n i =1 ( x i − ¯ x ) 2 n − 1 = ∑ n i =1 x 2 i − n ¯ x 2 n − 1 r xy = s xy s x s y s xy = ∑ n i =1 ( x i − ¯ x )( y i − ¯ y ) n − 1 = ∑ n i =1 x i y i − n ¯ x ¯ y n − 1 b = r xy s y s x = s xy s 2 x a = ¯ y − b ¯ x

Part 1: Multiple Choice Questions Please select the most correct answer. Please answer in the bubble sheet found on the last page by filling in the most correct answer (A, B, ..., E) next to the appropriate question. The following code is for Questions 1-5. dataset1 = c(6, 7, 8, 9) dataset2 = c(10, 12, 14, 16) Question 1 [1 mark] Based on the code above: (A) The mean of dataset1 is greater than the mean of dataset2. (B) The median of dataset1 is greater than the median of dataset2. (C) The median of dataset1 is greater than the median of dataset2. (D) The mean is equal to the median for each dataset. Question 2 [1 mark] The standard deviation for dataset2 is: (A) 1.29 (B) 1.67 (C) 2.58 (D) 6.67 Question 3 [1 mark] The variances are the same for both datasets. (A) TRUE (B) FALSE Question 4 [1 mark] What is the R code that will remove the first observation from dataset1? Select all that apply. (A) dataset1[-1] (B) dataset1[1] (C) dataset1[c(1,2,3)] (D) dataset1[c(2,3,4)] Question 5 [1 mark] Suppose the first observation is removed from dataset1. The sample variance for dataset1 would: (A) Increase. (B) Decrease. (C) Remain the same.