# 11.8. ExercisesΒΆ

1. The following sample file called studentdata.txt contains one line for each student in an imaginary class. The student’s name is the first thing on each line, followed by some exam scores. The number of scores might be different for each student.

joe 10 15 20 30 40
bill 23 16 19 22
sue 8 22 17 14 32 17 24 21 2 9 11 17
grace 12 28 21 45 26 10
john 14 32 25 16 89


Using the text file studentdata.txt write a program that prints out the names of students that have more than six quiz scores.

1. Using the text file studentdata.txt (shown in exercise 1) write a program that calculates the average grade for each student, and print out the student’s name along with their average grade.
1. Using the text file studentdata.txt (shown in exercise 1) write a program that calculates the minimum and maximum score for each student. Print out their name as well.
1. Here is a file called labdata.txt that contains some sample data from a lab experiment.

44 71
79 37
78 24
41 76
19 12
19 32
28 36
22 58
89 92
91 6
53 7
27 80
14 34
8 81
80 19
46 72
83 96
88 18
96 48
77 67


Interpret the data file labdata.txt such that each line contains a an x,y coordinate pair. Write a function called plotRegression that reads the data from this file and uses a turtle to plot those points and a best fit line according to the following formulas:

$$y = \bar{y} + m(x - \bar{x})$$

$$m = \frac{\sum{x_iy_i - n\bar{x}\bar{y}}}{\sum{x_i^2}-n\bar{x}^2}$$

where $$\bar{x}$$ is the mean of the x-values, $$\bar{y}$$ is the mean of the y- values and $$n$$ is the number of points. If you are not familiar with the mathematical $$\sum$$ it is the sum operation. For example $$\sum{x_i}$$ means to add up all the x values.

Your program should analyze the points and correctly scale the window using setworldcoordinates so that that each point can be plotted. Then you should draw the best fit line, in a different color, through the points.

1. At the bottom of this page is a very long file called mystery.txt The lines of this file contain either the word UP or DOWN or a pair of numbers. UP and DOWN are instructions for a turtle to lift up or put down its tail. The pairs of numbers are some x,y coordinates. Write a program that reads the file mystery.txt and uses the turtle to draw the picture described by the commands and the set of points.

Here is the mystery.txt file:

UP
-218 185
DOWN
-240 189
-246 188
-248 183
-246 178
-244 175
-240 170
-235 166
-229 163
-220 158
-208 156
-203 153
-194 148
-187 141
-179 133
-171 119
-166 106
-163 87
-161 66
-162 52
-164 44
-167 28
-171 6
-172 -15
-171 -30
-165 -46
-156 -60
-152 -67
-152 -68
UP
-134 -61
DOWN
-145 -66
-152 -78
-152 -94
-157 -109
-157 -118
-151 -128
-146 -135
-146 -136
UP
-97 -134
DOWN
-98 -138
-97 -143
-96 -157
-96 -169
-98 -183
-104 -194
-110 -203
-114 -211
-117 -220
-120 -233
-122 -243
-123 -247
-157 -248
-157 -240
-154 -234
-154 -230
-153 -229
-149 -226
-146 -223
-145 -219
-143 -214
-142 -210
-141 -203
-139 -199
-136 -192
-132 -184
-130 -179
-132 -171
-133 -162
-134 -153
-138 -145
-143 -137
-143 -132
-142 -124
-138 -112
-134 -104
-132 -102
UP
-97 -155
DOWN
-92 -151
-91 -147
-89 -142
-89 -135
-90 -129
-90 -128
UP
-94 -170
DOWN
-83 -171
-68 -174
-47 -177
-30 -172
-15 -171
-11 -170
UP
12 -96
DOWN
9 -109
9 -127
7 -140
5 -157
9 -164
22 -176
37 -204
40 -209
49 -220
55 -229
57 -235
57 -238
50 -239
49 -241
51 -248
53 -249
63 -245
70 -243
57 -249
62 -250
71 -250
75 -250
81 -250
86 -248
86 -242
84 -232
85 -226
81 -221
77 -211
73 -205
67 -196
62 -187
58 -180
51 -171
47 -164
46 -153
50 -141
53 -130
54 -124
57 -112
56 -102
55 -98
UP
48 -164
DOWN
54 -158
60 -146
64 -136
64 -131
UP
5 -152
DOWN
1 -150
-4 -145
-8 -138
-14 -128
-19 -119
-17 -124
UP
21 -177
DOWN
14 -176
7 -174
-6 -174
-14 -170
-19 -166
-20 -164
UP
-8 -173
DOWN
-8 -180
-5 -189
-4 -201
-2 -211
-1 -220
-2 -231
-5 -238
-8 -241
-9 -244
-7 -249
6 -247
9 -248
16 -247
21 -246
24 -241
27 -234
27 -226
27 -219
27 -209
27 -202
28 -193
28 -188
28 -184
UP
-60 -177
DOWN
-59 -186
-57 -199
-56 -211
-59 -225
-61 -233
-65 -243
-66 -245
-73 -246
-81 -246
-84 -246
-91 -245
-91 -244
-88 -231
-87 -225
-85 -218
-85 -211
-85 -203
-85 -193
-88 -185
-89 -180
-91 -175
-92 -172
-93 -170
UP
-154 -93
DOWN
-157 -87
-162 -74
-168 -66
-172 -57
-175 -49
-178 -38
-178 -26
-178 -12
-177 4
-175 17
-172 27
-168 36
-161 48
-161 50
UP
-217 178
DOWN
-217 178
-217 177
-215 176
-214 175
-220 177
-223 178
-223 178
-222 178
UP
-248 185
DOWN
-245 184
-240 182
-237 181
-234 179
-231 177
-229 176
-228 175
-226 174
-224 173
-223 173
-220 172
-217 172
-216 171
-214 170
-214 169
UP
-218 186
DOWN
-195 173
-183 165
-175 159
-164 151
-158 145
-152 139
-145 128
-143 122
-139 112
-138 105
-134 95
-131 88
-129 78
-126 67
-125 62
-125 54
-124 44
-125 38
-126 30
-125 27
-125 8
-126 5
-125 -9
-122 -15
-115 -25
-109 -32
-103 -39
-95 -42
-84 -45
-72 -47
-56 -48
-41 -47
-31 -46
-18 -45
-1 -44
9 -43
34 -45
50 -52
67 -61
83 -68
95 -80
112 -97
142 -115
180 -132
200 -146
227 -159
259 -175
289 -185
317 -189
349 -190
375 -191
385 -192
382 -196
366 -199
352 -204
343 -204
330 -205
315 -209
296 -212
276 -214
252 -208
237 -202
218 -197
202 -193
184 -187
164 -179
147 -173
128 -168
116 -164
102 -160
88 -158
78 -159
69 -162
57 -164
56 -165
51 -165
UP
68 -144
DOWN
83 -143
96 -141
109 -139
119 -146
141 -150
161 -155
181 -163
195 -169
208 -179
223 -187
241 -191
247 -193
249 -194
UP
-6 -141
DOWN
-15 -146
-29 -150
-42 -154
-51 -153
-60 -152
-60 -152
UP
-90 -134
DOWN
-85 -131
-79 -128
-78 -123
-80 -115
-82 -106
-80 -101
-76 -101
UP
-81 -132
DOWN
-76 -130
-71 -126
-72 -124
UP
43 -118
DOWN
44 -125
47 -135
41 -156
37 -160
40 -166
47 -171
47 -171
UP
-106 -153
DOWN
-107 -167
-106 -178
-109 -192
-114 -198
-116 -201

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