CHAPTER 1 EXERCISES 1. If a coin is fair, then heads and tails should have equal chance of occurring. a. Test the fairness of a coin by flipping it 10 times. b. Test the fairness of the same coin by flipping it 50 times. c. If heads and tails never reach 50-50 rate of occurrence, does this mean that the coin is unfair? Explain. No matter how many tosses you do, the coin remains fair, because the expected occurrence of head and tail is 50-50 %. This simply indicates that the probability is binomial and mutually exclusive and no other values will come out each time the coin is tossed. If ever the total occurrence of being a head of a tail does not reach a 50-50 chance, it is because the event is caused by chance and the probability of having equal number of occurrence or probability of success or failure is dependent on other factors. The 50-50 rate is but an expected event or sample size when tossing the coin. An expectation even in real life does not always hold true. 2. What is the difference between a population and a sample? The population is the entire group of individuals that we want information about. The sample is a subset of a population that we actually examine in order to gather information. Since it is usually, impractical to test every member of a population, a sample from the population is typically the best approach available. It should consider the following; a. Must be collected randomly as far as possible. b. Must be independent – collection or measurement of one observation should effect the value of any other. c. Must be large enough sample size (or replication) to be truly representative – this is why we say “ 5 is good, but 8 would be better, 10 or more is excellent” – and not fall to chance variation. d. “good” sample sizes depend on the study. e. For ecology and other field studies, often easy to collect hundreds of measurements quickly. Lab experiments sometimes 5 replications is terrific and perhaps all that is feasible. 3. How can the concepts of population and sample relate to deductive reasoning and inductive reasoning? Sample and population are two important basis of conclusion or reasoning. There are two types of reasoning: a) deductive reasoning makes reason out of a given general knowledge or population such that what is true to general population will also be true to a sample. Deductive / Probability Inductive / Statistics Deductive: population sample general specific Probability In deductive reasoning, thinking proceeds from general assumption to specific application General and Specific Aristotle and other early philosophers o Drawing conclusions through categorical syllogism o All philosophers are moral. Socrates is a philosopher. Therefore, Socrates rates is moral. o Resistance training makes one big and bulky increasing body mass. Sandi is resistance training. Therefore, Sandi will become big and bulky. Not sufficient as a source of new truth. All mammals have lungs. A rabbit is a mammal. Therefore, a rabbit has lungs. Inductive: sample population specific general Statistics Example: if you take a poll and note the voting preferences of this sample, we will be able to draw some conclusions about the votes of the population Conclusions about event …. Every rabbit that has been observed has lungs. Therefore, every rabbit has lungs. 4. A newspaper article reports that “this morning’s demonstration was attended by 8437 students.” Comment. The news report has specifically mentioned the actual head count of student attendees in the demonstration. However, if the newspaper account is not based on actual count, the figure given might be a wrong representation if it is only based on estimate. It could mean that the newspaper account could be attributed to the number of registrant that is actually recorded on paper which means that the actual number of demonstrator could be lesser or greater in number but because the number was on record the account was used. 5. A college conducts a survey of its alumni in an attempt to determine their median annual salary. Would alumni with very low salaries be likely to respond? How would this affect the result? Identify some other factors that might affect the result. Alumni with low salaries may or may not likely to respond in the survey depending on the situation, manner of conducting the survey and reason for the conduct of survey. The median may not be affected should they respond or not. Median measures the middle value. It is better measure for populations with possibly wide variations. 6. What differences are there between the following two statements, and which one do you believed is more accurate/ a. Drunken drivers cause more than half of all fatal car crashes. b. Of all fatal motor vehicle crashes, more than 50% involve alcohol. Between the two statements, I consider the first statement to be more accurate and precise. It has definitely and specifically stated that what causes more than half the fatal car crashes are drunken drivers; unlike in the second statement, fatal motor vehicle crashes were attributed to anything that involved alcohol but not necessarily and specifically identified as drunken drivers.