20. If the 7 scores in a sample were 84, 71, 69, 75, 73, 80, and 78, the standard deviation would be? Use the formula below to calculate the standard deviation. There is an example in the Example of Descriptive Statistics file and in the Handout file (p. 422). NEX' -(EX)2 S N(N - 1) 21. What is the shape of the frequency distribution shown here (see section 2 in the lecture notes)? (Just name the shape; you do not have to draw it unless you want to do so to get the answer) X 10 51 50 20 11 6