Algebra 2 P Experimental Design 11 5 Margin of Error

Transcription

1 Algebra 2 P Experimental Design 11 5 Margin of Error Nov 23 2:43 PM 11 4 Apr 27 10:17 AM 1

2 Controlled Experiment: Identical Conditions with the exception of one variable. Control Group: No Treatment Treatment Group: Gets Treatment Dec 4 11:05 AM Determine whether each study is a randomized comparative experiment. a. b. No Yes Example 1 2

3 Core Concept Apr 27 10:17 AM 3

4 Determine whether the following research topic is best investigated through an experiment or an observational study. You want to know whether flowers sprayed twice per day with a mist of water stay fresh longer than flowers that are not sprayed. Experiment You want to know whether vigorous exercise in older people results in longer life. Observational Study Monitoring Progress 2 Analyzing Experimental Designs Validity=Reliability and Replication=Repeating A pharmaceutical company wants to test the effectiveness of a new chewing gum designed to help people lose weight. Identify a potential problem, if any, with each experimental design. Then describe how you can improve it. a. The company identifies 10 people who are overweight. Five subjects are given the new chewing gum and the other 5 are given a placebo. After 3 months, each subject is evaluated and it is determined that the 5 subjects who have been using the new chewing gum have lost weight. b. The company identifies 10,000 people who are overweight. The subjects are divided into groups according to gender. Females receive the new chewing gum and males receive the placebo. After 3 months, a significantly large number of the female subjects have lost weight. c. The company identifies 10,000 people who are overweight. The subjects are divided into groups according to age. Within each age group, subjects are randomly assigned to receive the new chewing gum or the placebo. After 3 months, a significantly large number of the subjects who received the new chewing gum have lost weight. Example 3 4

5 11 5 Descriptive Stats: Involves the Organization, Summarization, and Displaying of Data Inferential Stats: Involves using a Sample to draw Conclusions about a Population Dec 4 11:14 AM You can use stats to make predictions, or Inferences, about a population. Estimating the Population Mean Estimate the population mean μ. Sample of 25 people... Dec 4 11:35 AM 5

6 Margin of Error Margin of Error estimates how accurate a number is considered to be from a given population. Based on Standard Deviation. The larger the sample, the smaller the Margin of Error n = sample size Margin of Error = (+/ ) 1 n Find the Margin of Error is the Sample Size is 100, 400, 800? Apr 27 10:09 AM Margin of Error Estimate the Sample Size if the Margin of Error is +/ 4% May 7 7:06 AM 6

7 May 7 6:42 AM HW P623 # P630 #3,4,15 18 Please put your name and class period at the top of the homework. Also include the homework number. Nov 23 2:44 PM 7

8 Experiment: Imposes a treatment on individuals in order to collect data on their response to the treatment. Observational Study: Observes individuals and measures variables without controlling the individuals or their environment. Dec 6 7:49 AM Core Concept 8

9 The numbers of friends for a random sample of 40 teen users of a social networking website are shown in the table. Estimate the population mean μ. Example 1 The data from another random sample of 30 teen users of the social networking website are shown in the table. Estimate the population mean μ. Monitoring Progress 1 9

10 In a survey of 2048 people in the U.S., 55% said that television is their main source of news. (a) What is the margin of error for the survey? (b) Give an interval that is likely to contain the exact percent of all people who use television as their main source of news. Example 4 In a survey of 1028 people in the U.S., 87% reported using the Internet. Give an interval that is likely to contain the exact percent of all people in the U.S. who use the Internet. Monitoring Progress 4 10