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Exercise 1: Data Interpretation Dissolved oxygen is oxygen that is trapped in a fluid. Since many living organisms require oxygen to survive, it is a necessary component of water systems (streams, lakes, rivers, etc.). Dissolved oxygen is measured in units of parts per million (ppm). Examine the data in Table 4, which shows the amount of dissolved oxygen present in a body of water and the number of fish observed in the sample. Then, answer the questions below. Table 4: Water Quality vs. Fish Population Dissolved Oxygen (ppm) 0 2 4 6 8 10 12 14 16 18 Number of Fish Observed 0 1 3 10 12 13 15 10 12 13 What patterns do you observe based on the information in Table 4? Through 12 parts per million of dissolved oxygen the number of fish increased as the dissolved oxygen increased, and the amount of dissolved oxygen was always greater than the number of fish observed. Develop a hypothesis relating to the amount of dissolved oxygen measured in the water sample and the number of fish observed in the body of water. According to the data, the correlation to the pattern of increase and decrease in number of fish to the consistent increase in dissolved oxygen is that because the fish need oxygen to survive so there cannot be more fish than oxygen to provide to the fish. What would your experimental approach be to test this hypothesis? To test this hypothesis, it would require measuring a body of water and counting the number of fish as the amount of dissolved oxygen is increased over a period of time. What would be the independent and dependent variables? Independent variable: Increase in dissolved oxygen Dependent variable: Increase/decrease in number of fish What would be your control? The control is the body of water not increasing in oxygen, but left alone. Exercise 2: Testable Observations Determine which of the observations below are testable. For those that are testable: Determine if the observation is qualitative or quantitative. Write a hypothesis and a null hypothesis. What would be your experimental approach? What are the dependent and independent variables? What are your controls - both positive and negative? How will you collect your data? How will you present your data (e.g., charts, graphs, types)? How will you analyze your data? Observations A plant grows 3 cm faster per day when placed on a window sill than it does when placed on a coffee table in the middle of the living room. Determine if the observation is qualitative or quantitative. Quantitative Write a hypothesis and a null hypothesis. Hypothesis: If a plant grows in the windowsill, it will grow faster than when placed on a coffee table in the middle of the living room. Null Hypothesis: If a plant grows in the windowsill it will grow at the same rate than when placed on a coffee table in the middle of the living room. What would be your experimental approach? Grow the same plant in the designated two spots and treat them the same and measure their growth every day at the same time. What are the dependent and independent variables? Dependent: growth of the plants. Independent: location of the plants What are your controls - both positive and negative? Positive: the plant in the windowsill. Negative: the plant placed on the coffee table. How will you collect your data? Measure the growth of the plant each night with a ruler or measuring tool of some sort. How will you present your data (e.g., charts, graphs, types)? A line graph to show the plants growth over time. How will you analyze your data? Once a certain time is reached, enter all of the data into some kind of document and portray it in a graph. Based on said graph it will reveal the results of whether one plant grew more than the other. And if the hypothesis is correct, it is best to repeat the experiment for validity and consistency. The bank teller with brown hair and brown eyes is taller than the other tellers. Not testable When Sally eats healthy foods and exercises regularly, her blood pressure is 10 points lower than when she eats fatty foods and does not exercise. Determine if the observation is qualitative or quantitative. Quantitative Write a hypothesis and a null hypothesis. Hypothesis: If Sally eats healthy foods and exercises regularly her blood pressure will be lower than when she eats fatty foods and does not exercise. Null Hypothesis: If Sally eats healthy foods and exercises regularly her blood pressure will be the same than when she eats fatty foods and does not exercise. What would be your experimental approach? Have Sally eat healthy foods and exercise regularly one week and measure her blood pressure each day. Then have her eat fatty foods and not regularly exercise the next week ad measure her blood pressure each day. What are the dependent and independent variables? Dependent: Sally’s blood pressure. Independent: the types of food and whether or not exercise is being done. What are your controls - both positive and negative? Positive: Sally exercising and eating healthy. Negative control: Sally not exercising and eating fatty foods. How will you collect your data? Measuring her blood pressure every day. How will you present your data (e.g., charts, graphs, types)? The data will be represented by a line graph. How will you analyze your data? By looking at the data represented in the graph and seeing if my hypothesis is proven and if so, have it repeated again for accuracy and consistency. The Italian restaurant across the street closes at 9 pm, but the restaurant two blocks away closes at 10 pm. Not testable For the past two days, the clouds have come out at 3 pm, and it has started raining at 3:15 pm. Not testable George did not sleep at all the night following the start of Daylight Savings Time. Not testable Exercise 3: Conversion Use Figure 9 to convert each value into the designated units. Figure 9: Conversions for temperature, time, mass, and length. 46,756,790 mg = 46.76kg 5.6 hours = 20,160 seconds 13.5 cm = 5.31 inches 47 °F = 116°C Exercise 4: Accuracy and Precision Determine whether the following statements are accurate, precise, both, or neither. Circle your answer. During gym class, four students decided to see if they could perform the norm of 45 sit-ups in one minute. The first student did 64 sit-ups, the second did 69, the third did 65, and the fourth did 67. Accurate Precise Both Neither The average score for the 5th-grade math test is 89.5. The top 5th graders took the test and scored 89, 93, 91, and 87. Accurate Precise Both Neither Yesterday the temperature was 89 °F, tomorrow it’s supposed to be 88 °F, and the next day it’s supposed to be 90 °F, even though the average temperature for September is 75 °F. Accurate Precise Both Neither Four friends decided to play horseshoes. They took a picture of their results: Accurate Precise Both Neither A local grocery store held a contest to see who could most closely guess the number of pennies inside a large jar. The first six people guessed the numbers 735, 209, 390, 300, 1005, and 689. The grocery clerk said the jar actually contains 568 pennies. Accurate Precise Both Neither Exercise 5: Significant Digits And Scientific Notation Part 1 Determine the number of significant digits in each number, and write the specific significant digits. 405000 – 3 (4,0,5) 0.0098 – 2 (9,8) 39.999999 – 8 (3,9,9,9,9,9,9,9) 13.00 – 4 (1,3,0,0) 80,000,089 – 8 (8,0,0,0,0,0,8,9) 55,430.00 – 7 (5,5,4,3,0,0,0) 0.000033 – 2 (3,3) 620.03080 – 8 (6,2,0,0,3,0,8,0) Part 2 Convert each number into scientific notation. 70,000,000,000 – 7 x 10^10 0.000000048 – 4.8 x 10^-8 67,890,000 – 678.9 x 10^5 70,500 – 70.5 x 10^3 450,900,800 – 450900.8 x 10^3 0.009045 – 904.5 x 10^-5 0.023 – 2.3 x 10^-2 Exercise 6: Percentage Error Determine the percentage error in each scenario. Show your work on all problems. A dad holds five coins in his hand. He tells his son that if he can guess the amount of money he is holding within 5% error, he can have the money. The son guesses that dad is holding 81 cents. The dad opens his hand and displays 90 cents. Did the son guess close enough to get the money? No, the sons percent error was 11% A science teacher tells her class that their final project requires students to measure a specific variable and determine the velocity of a car with no more than 2.5% error. Jennifer and Johnny work hard and decide the velocity of the car is 34.87 m/s. The teacher informs them that the actual velocity is 34.15 m/s. Will Jennifer and Johnny pass their final project? No, their percent error was 2.1% A train is on its way from Chicago, IL to Madison, WI. The trip is said to last 3.15 hours. When the train arrives in Madison, the conductor notices the trip took 3.26 hours. The train company prides itself on always having its trains arrive within a 3% error of the expected time. Will the train company live up to its reputation on this trip? No, it was a 3.3% error. A coach tells his Little League players that hitting a 0.275 batting average, within 7% error, means that they had a really great season. Seven-year-old Tommy ended the season with a 0.258 batting average. According to his coach, did Tommy have a great season? Yes, he ended with a 6.1% batting average error. Exercise 7: Experimental Variables Determine the variables tested in each of the following experiments. If applicable, determine and identify any positive or negative controls. A study is being done to test the effects of habitat space on the size of fish populations. Different sized aquariums are set up with six goldfish in each one. Over a period of six months, the fish are fed the same type and amount of food. The aquariums are equally maintained and cleaned throughout the experiment. The temperature of the water is kept constant. At the end of the experiment, the number of surviving fish are surveyed. A. Independent Variable: size of aquarium B. Dependent Variable: number of fish C. Controls: time, diet type/amount, aquarium maintenance, temperature To determine if the type of agar affects bacterial growth, a scientist cultures E. coli on four different types of agar. Five petri dishes are set up to collect results: • One with nutrient agar and E. coli • One with mannitol-salt agar and E. coli • One with MacConkey agar and E. coli • One with LB agar and E. coli • One with nutrient agar but NO E. coli A. Independent Variable: type of agar B. Dependent Variable: bacterial growth C. Controls: agar with no E.coli
