strategy 14 Grid in Answers to Data Questions Your ability to calculate the exact answer to a problem will be tested on the TASC Mathematics Test using grid-in questions. Review these rules for entering an answer into a number grid: Your answer must fit within the five columns on If you use a fraction slash or a decimal point, it must occupy its own column. Enter mixed numbers as improper fractions. There may be more than one correct way to present an answer. For instance, an answer might be correct in either fraction or decimal form. Some answers to data analysis questions are ratios or percents. To enter a ratio as the answer to a problem, express it as a fraction. You do not have to simplify the ratio to lowest terms as long as it will fit within the five columns. For probability questions, express chance as either a decimal or a fraction. You cannot grid in a percent because the number grid does not contain the % symbol. Example Farah shipped four packages to Los Angeles today. The weights of the packages were 2.8, 3.6, 1.8, and 2.6 pounds. What is the median shipping weight of the packages? Think: The median weight is the middle value. However, since there is an even number of packages, two weights will be in the middle. Step 1: Write the weights in order: 3.6 2.8 2.6 1.8 Step 2: Find the average of the two middle weights: (2.8 + 2.6) 2 = 2.7 Solution: The median weight of the packages is 2.7 pounds. 2. 7 TASC Problem 1 A school sold 125 raffle tickets. If Rachel bought 5 tickets, what is the probability that one of Rachel s tickets will win? Mark your answer in the circles in Think: I can use the probability ratio to answer the question. desiredoutcomes Step 1: Write the ratio: possible outcomes 5 = 125 Step 2: Write the answer in Since 5/125 will fit in five columns, you don t have to reduce the fraction. However, you could reduce it to 1/25 or change it to a decimal: 0.04. Any of these answers would be scored as correct. Answer: Two ways to mark the grid are shown to the right. 5 / 1 2 5 0. 0 4 testwise Always enter your answer in the top row of the grid, writing one number or symbol to a box. Then fill in the circles in the grid below. Fill in the circles carefully. Only the circles are scored. Your answer at the top of the grid will not be graded. New Readers Press. All rights reserved. 34 Unit 3: Sample Space and Probability Strategies
Apply the Strategy Directions: For questions 1 3, first decide whether to express your answer as a whole number, a fraction, or a decimal. Then solve. You may use your calculator as needed. Questions 1 and 2 refer to the following graph. Swim Team Budget (Total Budget $2,000) Pool Fees 36% Uniforms 16% Bus 40% 3. Tim has six pairs of black socks and six pairs of brown socks in a drawer. He reaches in and takes out one pair of black socks. If he selects another pair at random, what is the chance that the pair will be black? New Readers Press. All rights reserved. Tournament Fees 8% 1. What is the ratio of the expense for uniforms to the expense for buses? 2. What amount, in dollars, is budgeted for pool fees? Answers start on page 46. 4. Calvin works in a hotel. He received the following numbers of tips during each hour of his shift: Hour 1: 3 tips Hour 2: 6 tips Hour 3: 5 tips Hour 4: 6 tips Hour 5: 4 tips Hour 6: 6 tips What is the mode of the numbers of tips Calvin received per hour? 5. A football team scores the following points during its first five games of the season: 31, 35, 54, 14, and 31. After the sixth game, the average falls to 29.5. How many points did the team score in the sixth game? 6. A game has a 24-card deck. The deck has 12 blue cards numbered from 1 through 12, and 12 red cards numbered from 1 through 12. What is the probability of drawing a red card equal to or greater than 7? Unit 3: Sample Space and Probability Strategies 35
Using Grid for Probability Problems 1. 2/5 16% /40% or 2/5 2 / 5 fraction 2. 36% of $2000 =.36 * 2000 = $720 7 2 0 Whole number 3. 5 / 2 2 P(Black1) = desired outcomes/total outcomes = 6/12 = ½ P(Black2 Black1) = 5/11 (only 5 pairs of black socks to choose now and only 11 pairs left) P(Black1 and Black2) = ½ * (5/11) = 5/22
Fraction 4. 6 Step 1: Mode is the most frequent value in a list of data 3 tips once 4 tips once 5 tips once 6 tips three times So, 6 tips is the mode 5. 1 2 Step 1: Average = Sum of scores/number of scores Let x = points scored in the sixth game Step 2: Write an equation for the average points scored after six games (31 + 35 + 54 + 14 + 31 + x) /6 = 29.5 ( 165 + x)/6 = 29.5 165 + x = 177 (multiply each side by 6) x = 12
6. 3 / 8 Step 1: P(red) = 12/24 = ½ Step 2: P(7 or greater) = 18/24 = ¾ Step 3: P(red and 7 or greater) = ½ * ¾ = 3/8