Stat 200 Lab 10 The null hypothesis is a statement that nothing is happening It may be a statement that there is no relationship or no difference or that the status quo is correct The alternative hypothesis is a statement that that there is a relationship or there is a difference or that the status quo is incorrect Most often researchers hope to prove that the alternative hypothesis is the correct explanation of their situation Activity 1 For each of the following situations write null and alternative hypotheses Be as specific as possible a Up until the 1980s it was usually stated that the mean height of men was 69 inches Researchers now think that the mean height of men is greater than this value b In a recent class we compared men and women with regard to the proportion who found it easiest to make friends with the opposite sex c Last week in Stat 100 I asked students to randomly choose on of the numbers 1 2 10 With random picking the chance of picking the number 7 is 1 10 I believe that people are more likely than this to pick the number 7 d Is there a relationship between the hours per day that students study and the hours per day that they sleep e A researcher asks pregnant women to predict the sex of their babies The researcher thinks that the proportion of correct guesses will be higher than the proportion that results from chance luck Page 2 A test statistic is summary of the data that can be used to decide between the null and alternative hypothesis A p value is the probability that an observed test statistic would be as large as it is or larger if the null hypothesis is true A statistically significant result is one for which the p value is 0 05 This is usually interpreted as evidence in favor of the alternative hypothesis Activity 2 In the Stat 100 number picking activity described in the previous activity 40 students out of n 183 picked the number 7 Use Minitab to determine a p value for deciding between H0 p 0 10 and Ha p 0 10 What s the value of p What is the p value of the test What is the conclusion about the null and alternative hypotheses Minitab Help Use Stat Basic Stats 1 Proportion Use the Options button to set up the details of the test You ve got Summarized Data Activity 3 In a February Gallup Poll about 50 of the respondents said they believed in love at first sight Let p proportion of college students who believe in love at first sight What null and alternative hypothesis do you think would be appropriate The class data for this question is we ll supply it Use Minitab to test your null and alternative hypotheses What is your conclusion You won t be able to do this until we get you the data Stat 200 Lab 10 Survey 1 Do you believe in love at first sight Yes No or Don t Know 2 Do you think there is extra terrestrial life Yes No Don t Know 3 In a typical day about how long do you spend watching television 4 About how many minutes do you spend for a typical shower minutes 5 What is you sex Stat 200 Lab 10 Attendance Name Section Last 4 digits of ID Stat 200 Lab 10 Attendance Name Section Last 4 digits of ID
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