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Math 20-2 Statistics Statistics Mid-Unit Review 1. The following list gives the weight, in pounds, of the members of the Edmonton Eskimos football team: 165 170 175 183 185 185 185 188 188 189 191 195 195 196 197 205 205 210 210 210 210 215 215 216 225 225 229 230 235 235 240 248 250 255 255 265 270 300 300 300 300 302 310 315 320 335 a) Use your calculator to find the mean, median, mode, standard deviation, and range of the weights. Round to the nearest tenth. (Don’t forget units!) b) Complete the frequency table, then make a histogram or frequency polygon of the data. (Don’t forget to label and scale the axes!) Weight (lb) 160-175 Frequency 175-190 190-205 c) Put the frequency table into L1 and L2 in your calculator, and then find the mean, median, and standard deviation again. How do they compare to the answers you got in part a? d) Describe how the data is distributed. Does it appear to be a normal distribution? Explain. Math 20-2 Statistics 2. Twila and Amber keep a log of the amount of time, in minutes, they spend doing homework each school day for two weeks: Twila: Amber: 45 80 55 10 50 65 40 15 55 75 40 30 60 40 45 85 40 20 35 35 a) Find the mean, median, mode, range and standard deviation for each girl’s homework times. Round to the nearest tenth, if necessary. b) Who spends more time on homework, on average? c) Who is more consistent? Explain. 3. Tyson wants to buy a new cell phone. He researched the cell phone he was considering buying and learned that the lifetime of the phone was normally distributed with a mean of 30 months and a standard deviation of 6 months. a) Mark the intervals on the normal distribution curve below. (Don’t forget to label the horizontal axis.) 34% 0.15% 34% 2.35% 2.35% 13.5% 13.5% 0.15% b) If Tyson purchases this cell phone, what is the likelihood that it will last longer than 3 years? c) The company will replace cell phones that last less than 18 months. In a shipment of 350 phones, approximately how many will they have to replace? Math 20-2 Statistics 4. On a recent Math 30-2 diploma exam, 99.7% of students in Alberta got between 35% and 89%. If the marks were normally distributed, find the mean and standard deviation of the marks. 34% 0.15% 34% 2.35% 2.35% 13.5% 13.5% 0.15% 5. The company payroll of Sweetwater Communications has a mean monthly salary of $5400 with a standard deviation of $800, as represented by the normal curves below. a) Employees at Clearstream Communication Technologies have a mean monthly salary of $5400 as well, but a standard deviation of $950. Sketch this normal distribution on the same axis as Sweetwater’s. b) The employees at Sweetwater Communications are all going to receive a raise of $150 per month. Sketch the new normal distribution on the axis below.