Chapter 8 Statistics What is statistics Statistics the

Chapter 8 Statistics

What is statistics? Statistics – the practice or science of collecting and analyzing numerical data in large quantities, especially for the purpose of inferring proportions in a whole from those in a representative sample.

How is data collected?

Determine whether each situation describes a survey, an experiment, or an observational study. Then identify the sample, and suggest a population from which it may have been selected. 1. The school administrators want to start an after-school tutoring program. They send a questionnaire to 100 students randomly selected from those who had a grade-point average less than 2. 8. 2. You want to know how students and parents feel about school uniforms. 3. A research group wants to determine if playing music in a patient waiting room reduces stress levels. 4. A nutrition research group wants to determine whether ninth-grade students who reported having eating breakfast every school morning had higher standardized test scores than who did not report having eaten breakfast every school morning. 5. A restaurant plans to ask 100 randomly selected customers to determine which menu item is most popular. 1. This 3 Experiment; is a survey, sample because answer: the data A sample are collected of patients from participants’ two different responses waiting in the questionnaire. rooms willsample need The sample to be is the students who received questionnaire, the 4. Observational study; sample answer: Theobtained scores offrom thethe participants areby and 5. Survey; answer: The 100 data will be opinions given members 2. This calls survey. It iswithout best to obtain thethe data by asking a less random population tested, which isfor allaof means the students that thewho members had a being grade-point of sample average will be affected thansample 2. 8. by the of observed and compared them affected by the study. of the sample students and a random sample of parents to give their opinions study. population.

Make Inferences Once data have been collected using a random sample, you can analyze the data to calculate a sample statistic and make inferences about the population. In some cases, you can make an inference about the population without knowing the size of the population. What information can we gain from this graph? This graph shows a random sample of the 5000 employees at a company that were surveyed about the type of pet they own. Based on the results in the graph, what is the most reasonable inference about the number of employees who own a dog?

Make Inferences A student chose a random sample of 4% of the athlete’s at a school. The student found that 5 of the athletes were boys. What is the most reasonable inference about the number of athletes at the school that are boys?

Make Inferences A random sample of the 2000 students at an elementary school were surveyed about their favorite color. Based on the results in the graph, what is the most reasonable inference about the number of students who chose pink as their favorite color?

Make Inferences A random sample of 20% of the teachers in a district was chosen. It was found that 40 of the teachers were female. What is the most reasonable inference about the number of teachers in the district that are female?

Make Inferences CLASS PRESIDENT A random sample of the 6000 students were surveyed about the candidate they would vote for in an election about class president. Based on the results in the graph, what is the most reasonable inference about the number of students who will vote for Gia in the class president election?

Make Inferences TELECOMMUNICATIONS A random sample of the 250, 000 people who purchase a telecommunications package (internet, cable, satellite, etc. ) were surveyed about the company they prefer. Based on the results in the graph, what is the most reasonable inference about the number of people who Prefer… a) Company B a) Company A a) Company C and D

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