WHAT I REALLY WANT TO SEE ON YOUR TEST HYPOTHESES TESTS STATE: Ho & Ha – clearly label what each one represent! NO HATS FOR Hos PLAN: Name of the test & CONDITIONS DO: MINIMUM – use the magic calculator buttons. Find the z- or t-statistic & the p-value. CONCLUDE: Compare pvalue with alpha, (fail to) reject the Ho, make convincing evidence conclusion based on Ha, IN CONTEXT.

Statistics People Get in groups of 3 please. You will need a calculator and several half sheets of paper.

1 In a recent poll, a researcher was curious the proportion of residents in Georgia have admitted to using some type of illegal drug once in their life. A Simple random sample of 110 West Cobb residents and 85 South Cobb residents found that 26 West Cobb residents and 21 South Cobb Residents admitted to using illegal drugs at least once in their lifetime. What is the standard deviation of the sampling distribution (not pooled) for ?

#1 Answer

#2 The life expectancy of men in the US is 79.5 years (with a standard deviation of 3.8 years) and the life expectance of women in the US is 83 years (with a standard deviation of 4.2 years.) A simple random sample is taken of 25 men and 36 women. What is the mean and standard deviation of the sampling distribution ?

Answer #2 Mean=3.5 Std dev=

#3 A sportswriter would like to see if there are more points scored now in college football than ten years ago. She does a SRS from 2005 of 30 teams and a SRS of 30 teams from 2015. Her results follow. Give a 98% confidence interval and state whether you think there is a difference in points scored. Assume all conditions have been met. (Calculator Ok)

ANSWER #3 (.3388, 6.6612) (this was xbar 2015-xbar 2005) Since 0 is not in the interval there is evidence to suggest that the scoring is different in 2015.

#4 Which of the following would make it inappropriate to use the 2 sample t-procedures? List all that apply. A) Standard deviations not the same B) Using a conservative degrees of freedom C) The population is not normal and the sample size is 60. D) Sampling error E) Measuring the difference in ACT scores for a group of students after taking a class on preparing for the ACT.

#4 Answers D and E

#5 You are interested in the opinion of males vs females on the subject of too much sexual material in prime-time TV. You ask 210 males and 185 females if they think they think there is too much sexual material on prime time TV. 123 males said yes, 121 females said yes. At the 5% level, find and interpret the p-value in the context of the problem. Assume all conditions have been met for inference.

#5 answer P- value = 0.163. At any reasonable alpha level there is NOT evidence to reject the null hypothesis. We can assume the views of males and females are NOT different.

#6 Do students in America take less years of math in college then in Great Britain? A SRS from 500 students in America and 400 students in Great Britain is conducted. The summary statistics are: At the 5% level is there evidence that Americans take Less math than residents of Great Britain. Find and interpret the p-value. Assume all conditions have been satisfied.

#6 Answer P-value = .005 At any reasonable alpha level there is evidence to reject the null hypothesis. It looks like the number of years of math are different for Great Britain. (great Britain higher)

#7 What test/procedure would be appropriate for the following You are interested if the proportion of males who attend church regularly is the same as the proportion of females. You are interested if a new drug lowered blood pressure for a group of subjects. Each subject has blood pressure before taking the drug and then after. You would like to estimate the average GPA of a senior at Pope High School Do teenagers in Georgia pay the same for car insurance (on average) as the teens in Alabama?

7 answer A) 2 prop z test B) Matched pairs test C) Confidence interval for mean D) 2 sample t-test.